THE  ORIGIN  AND  NATURE  OF  THE 

EMOTIONS 


GEORGE  W.  CRILE,  M.  D. 

Phylo.c«enetic  Association  in  Relation  to  Certain  Medical  Problems 

Phyloilc'.nef  ic  Association  in  Relation  to  the  Emotions 

1 'ain,  Lauijhter,  and  Crying 

'J'he  Kelalion  fielwcen  the  Pliysic,-il  State  of  the  Brain  Cells  and  Brain 

l\iixlions  —  Experimental  and  Clinical 

A  Mechanistic  View  of  Psychology 

A  Mechanistic  Theory  of  Disease 

The  Kinetic  System 

Alkalescence,  Acidily,  .md  Anesthesia—  A  Theory  of  Anesthesia 


Pttrrljaa?!!  by  % 


THE  ORIGIN  AND  NAl  URl^ 


of  the 


EMOTIONS 


Miscellaneous  Papers 


GEORGE   W.  CRILE,  M.D. 

PROIESSOR    Ol     SURCF.RV.    SCHOOL    OF    MEDICINE.    WESTERN    RESERVE    fNIVERSlTY 
VISITING    SURGEON    TO    THE    LAKESIDE    HOSPITAL,    CLEVELAND 


EDITED    BY 

AMY  F.  ROWLAND,  B.  S. 


^ 


PHILADELPHIA  AND  LONDON 


W.  B.  SAUNDERS   COMPANY 

1915 


^ 


Copyright,  1915,  by  W.  B.  Saunders  Company 


I 


PRINTED    IN   AMERICA 


PREFACE 

In  response  to  numerous  requests  I  have  brought  to- 
gether into  this  volume  eight  papers  which  may  serve  as  a 
supplement  to  the  volumes  previously  published*  and  as  a 
preface  to  monographs  now  in  preparation. 

In  the  first  of  these  addresses,  the  Ether  Day  Address, 
delivered  at  the  ^Massachusetts  General  Hospital  in  October, 
1910,  I  first  enunciated  the  Kinetic  Theory  of  Shock,  the 
key  to  which  was  found  in  laboratory  researches  and  in  a 
study  of  Darwin's  "Expression  of  the  Emotions  in  Man  and 
in  Animals,"  whereby  the  phylogenetic  origin  of  the  emo- 
tions was  made  manifest  and  the  pathologic  identity  of  sur- 
gical and  emotional  shock  was  established.  Since  1910  my 
associates  and  I  have  continued  our  researches  through — 
(a)  Histologic  studies  of  all  the  organs  and  tissues  of  the 
body;  (b)  Estimation  of  the  H-ion  concentration  of  the 
blood  in  the  emotions  of  anger  and  fear  and  after  the  applica- 
tion of  many  other  forms  of  stimuli;  (c)  Functional  tests 
of  the  adrenals,  and  (d)  Clinical  observations. 

It  would  seem  that  if  the  striking  changes  produced  by 
fear  and  anger  and  by  physical  trauma  in  the  master  organ 
of  the  body — the  brain — were  due  to  ivork,  then  we  should 
expect  to  find  corresponding  histologic  changes  in  other 
organs  of  the  body  as  well.     We  therefore  examined  every 

*  Surgical  Shock,  1899;  Surgery  of  the  Respiratory  System,  1899;  Prob- 
lems Relating  to  Surgical  Operations,  1901;  Blood  Pressure  in  Surgery, 
1903;  Hemorrhage  and  Transfusion,  1909;  Anemia  and  Resuscitation,  1914; 
and  Anoci-association,  1914  (with  Dr.  W.  E.  Lower). 

iii 


IV  PREFACE 

organ  and  tissue  of  the  bodies  of  animals  which  had  been 
subjected  to  intense  fear  and  anger  and  to  infection  and 
to  the  action  of  foreign  proteins,  some  animals  being 
killed  immediately;  some  several  hours  after  the  immediate 
effects  of  the  stimuli  had  passed;  some  after  seances  of 
strong  emotion  had  been  repeated  several  times  during 
a  week  or  longer. 

The  examination  of  all  the  tissues  and  organs  of  these 
animals  showed  changes  in  three  organs  only,  and  with  few 
exceptions  in  all  three  of  these  organs — the  brain,  the 
adrenals,  and  the  liver.  The  extent  of  these  changes  is  well 
shown  by  the  photomicrographs  which  illustrate  the  paper 
on  "The  Kinetic  System"  which  is  included  in  this  volume. 
This  paper  describes  many  experiments  which  show  that 
the  brain,  the  adrenal,  and  the  liver  play  together  con- 
stantly and  that  no  one  of  these  organs — as  far  at  least  as 
is  indicated  by  the  histologic  studies^can  act  without  the 
co-operation  of  the  other  two. 

Another  striking  fact  which  has  been  experimentally 
established  is  that  the  deterioration  of  these  three  organs 
caused  by  emotion,  by  exertion,  and  by  other  causes  is  largely 
counteracted,  if  not  exclusively,  during  sleep.  If  animals 
exhausted  by  the  continued  application  of  a  stimulus  are 
allowed  complete  rest  for  a  certain  number  of  hours,  with- 
out sleep,  the  characteristic  histologic  appearance  of  ex- 
haustion in  the  brain,  adrenals,  and  liver  is  not  altered 
notably,  whereas  in  animals  allowed  to  sleep  for  the  same 
number  of  hours  the  histologic  changes  in  these  organs  are 
lessened — in  some  cases  obliterated  even. 

This  significant  phenomenon  and  its  relation  will  be  dealt 
with  in  a  later  monograph. 


PREFACE  V 

Many  of  the  arguments  and  illustrations  by  which  the 
primary  premises  were  established  are  repeated — a  few  in 
all — many  in  more  than  one  of  these  addresses.  It  will  be 
observed,  however,  that  the  application  of  these  premises 
varies,  and  that  their  significance  broadens  progressively. 

In  the  Ether  Day  Address  the  phylogenetic  key  supplied 
by  Darwin  was  utilized  to  formulate  the  principle  that  the 
organism  reacts  as  a  unit  to  the  stimuli  of  physical  injury, 
of  emotion,  of  infection,  etc.  To  the  study  of  these  re- 
actions (transformations  of  energy)  the  epoch-making  work 
of  Sherrington,  "The  Integrative  Action  of  the  Nervous 
System,"  gave  an  added  key  by  which  the  dominating  role 
of  the  brain  was  determined.  Later  the  original  work  of 
Cannon  on  the  adrenal  glands  gave  facts,  and  an  experimen- 
tal method  by  which  Darwin's  phylogenetic  theory  of  the 
emotions  was  further  elaborated  in  other  papers,  especially 
in  the  one  entitled  ''Phylogenetic  Association  in  Relation 
to  the  Emotions,"  read  before  The  American  Philosophical 
Society  in  April,  1911. 

George  W.  Crile. 

Cleveland,  Ohio,  February,  1915. 


CONTENTS 


PAGE 


Phylogenetic  Association  in  Relation  to  Certain  Med- 
ical Problems 1 

Phylogenetic  Association  in  Relation  to  the  Emotions  .  .     55 

Pain,  Laughter,  and  Crying 77 

The  Relation  between  the  Physical  State  of  the  Brain- 
cells  and  Brain  Functions — Experimental  and  Clin- 
ical      Ill 

A  Mechanistic  View  of  Psychology 127 

A  Mechanistic  Theory  of  Disease 157 

The  Kinetic  System 173 

Alkalescence,  Acidity,  Anesthesia — A  Theory  of  Anes- 
thesia     227 

Index 237 


THE  ORIGIN  AND  NATURE   OF  THE 
EMOTIONS 


PHYLOGENETIC  ASSOCIATION  IN  RELATION  TO  CERTAIN 
MEDICAL  PROBLEMS* 

The  discovery  of  the  anesthetic  properties  of  ether  and 
its  practical  appHcation  to  surgery  must  always  stand  as 
one  of  the  great  achievements  of  medicine.  It  is  eminently 
fitting  that  the  anniversary  of  that  notable  day,  when  the 
possibilities  of  ether  were  first  made  known  to  the  world, 
should  be  celebrated  within  these  walls,  and  whatever  the 
topic  of  your  Ether  Day  orator,  he  must  fittingly  pause  first 
to  pay  tribute  to  that  great  event  and  to  the  master  surgeons 
of  the  Massachusetts  General  Hospital.  On  this  occasion, 
on  behalf  of  the  dumb  animals  as  well  as  on  behalf  of  suffer- 
ing humanity,  I  express  a  deep  sense  of  gratitude  for  the 
blessings  of  anesthesia. 

Two  years  ago,  an  historic  appreciation  of  the  discovery 
of  ether  was  presented  here  by  Professor  Welch,  and  last 
year  an  address  on  medical  research  was  given  by  President 
Eliot.  I,  therefore,  will  not  attempt  a  general  address,  but 
will  invite  your  attention  to  an  experimental  and  clinical 
study.  In  presenting  the  summaries  of  the  large  amount  of 
data  in  these  researches,  I  acknowledge  with  gratitude  the 

*  Address  delivered  at  the  Massachusetts  General  Hospital  on  the  sixty- 
fourth  anniversary  of  Ether  Day,  Oct.  15,  1910. 
1  1 


I  THE    EMOTIONS 

great  assistance  rendered  by  my  associates,  Dr.  D.  H. 
Dolley,  Dr.  H.  G.  Sloan,  Dr.  J.  B.  Austin,  and  Dr.  M.  L. 
Menten.* 

The  scope  of  this  paper  may  be  explained  by  a  concrete 
example.  When  a  barefoot  boy  steps  on  a  sharp  stone  there 
is  an  immediate  discharge  of  nervous  energy  in  his  effort 
to  escape  from  the  wounding  stone.  This  is  not  a  voluntary 
act.  It  is  not  due  to  his  own  personal  experience — his 
ontogeny — but  is  due  to  the  experience  of  his  progenitors 
during  the  vast  periods  of  time  required  for  the  evolution  of 
the  species  to  which  he  belongs,  i.  e.,  his  phylogeny.  The 
wounding  stone  made  an  impression  upon  the  nerve  receptors 
in  the  foot  similar  to  the  innumerable  injuries  which  gave 
origin  to  this  nerve  mechanism  itself  during  the  boy's  vast 
phylogenetic  or  ancestral  experience.  The  stone  supplied 
the  phylogenetic  association,  and  the  appropriate  discharge 
of  nervous  energy  automatically  followed.  If  the  sole  of  the 
foot  be  repeatedly  bruised  or  crushed  by  a  stone,  shock  may 
be  produced;  if  the  stone  be  only  lightly  applied,  then  the 
consequent  sensation  of  tickling  causes  a  discharge  of  ner- 
vous energy.  In  like  manner  there  have  been  implanted  in 
the  body  other  mechanisms  of  ancestral  or  phylogenetic 
origin  whose  purpose  is  the  discharge  of  nervous  energy  for 
the  good  of  the  individual.  In  this  paper  I  shall  discuss  the 
origin  and  mode  of  action  of  some  of  these  mechanisms  and 
their  relation  to  certain  phases  of  anesthesia. 

The  word  anesthesia — meaning  without  feeling — describes 
accurately  the  effect  of  ether  in  anesthetic  dosage.  Although 
no  pain  is  felt  in  operations  under  inhalation  anesthesia,  the 

*  From  the  H.  K.  Gushing  Laboratory  of  Experimental  Medicine,  Western 
Reserve  University,  Cleveland. 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS      6 

nerve  impulses  excited  by  a  surgical  operation  still  reach  the 
brain.  We  know  that  not  every  portion  of  the  brain  is  fully 
anesthetized,  since  surgical  anesthesia  does  not  kill.  The 
question  then  is:  What  effect  has  trauma  under  surgical 
anesthesia  upon  the  part  of  the  brain  that  remains  awake f 
If,  in  surgical  anesthesia,  the  traumatic  impulses  cause  an 
excitation  of  the  wide-awake  cells,  are  the  remainder  of  the 
cells  of  the  brain,  despite  anesthesia,  affected  in  any  way? 
If  so,  they  are  prevented  by  the  anesthesia  from  expressing 
that  influence  in  conscious  perception  or  in  muscular  action. 
Whether  the  anesthetized  cells  are  influenced  or  not  must  be 
determined  by  noting  the  physiologic  functions  of  the  body 
after  anesthesia  has  worn  off,  and  in  animals  by  an  examina- 
tion of  the  brain-cells  as  well.  It  has  long  been  known  that 
the  vasomotor,  the  cardiac,  and  the  respiratory  centers  dis- 
charge energy  in  response  to  traumatic  stimuli  applied  to 
various  sensitive  regions  of  the  body  during  surgical  anes- 
thesia. If  the  trauma  be  sufficient,  exhaustion  of  the  entire 
brain  will  be  observed  after  the  effect  of  the  anesthesia  has 
worn  off;  that  is  to  say,  despite  the  complete  paralysis  of 
voluntary  motion  and  the  loss  of  consciousness  due  to  ether, 
the  traumatic  impulses  that  are  known  to  reach  the  awake 
centers  in  the  medulla  also  reach  and  influence  every  other 
part  of  the  brain.  Whether  or  not  the  consequent  functional 
depression  and  the  morphologic  alterations  seen  in  the  brain- 
cells  may  be  due  to  the  low  blood-pressure  which  follows 
excessive  trauma  is  shown  by  the  following  experiments: 
The  circulation  of  animals  was  first  rendered  static  by  over- 
transfusion,  and  was  controlled  by  a  continuous  blood- 
pressure  record  on  a  drum,  the  factor  of  anemia  being  thereby 
wholly  excluded  during  the  application  of  the  trauma  and 


4  THE    EMOTIONS 

during  the  removal  of  a  specimen  of  brain  tissue  for  histologic 
study.  In  each  instance,  morphologic  changes  in  the  cells 
of  all  parts  of  the  brain  were  found,  but  it  required  much 
more  trauma  to  produce  brain-cell  changes  in  animals  whose 
blood-pressure  was  kept  at  the  normal  level  than  in  the 
animals  whose  blood-pressure  was  allowed  to  take  a  down- 
ward course.  In  the  cortex  and  in  the  cerebellum,  the 
changes  in  the  brain-cells  were  in  every  instance  more  marked 
than  in  the  medulla. 

There  is  also  strong  negative  evidence  that  traumatic  im- 
pulses are  not  excluded  by  ether  anesthesia  from  the  part  of 
the  brain  that  is  apparently  asleep.  This  evidence  is  as 
follows :  If  the  factor  of  fear  be  excluded,  and  if  in  addition 
the  traumatic  impulses  be  prevented  from  reaching  the  brain 
by  cocain*  blocking,  then,  despite  the  intensity  or  the  dura- 
tion of  the  trauma  within  the  zone  so  blocked,  there  follows 
no  exhaustion  after  the  effect  of  the  anesthetic  disappears, 
and  no  morphologic  changes  are  noted  in  the  brain-cells. 

Still  further  negative  evidence  that  inhalation  anesthesia 
offers  little  or  no  protection  to  the  brain-cells  against  trauma 
is  derived  from  the  following  experiment:  A  dog  whose 
spinal  cord  had  been  divided  at  the  level  of  the  first  dorsal 
segment,  and  which  had  then  been  kept  in  good  condition 
for  two  months,  showed  a  recovery  of  the  spinal  reflexes, 
such  as  the  scratch  reflex,  etc.  Such  an  animal  is  known  as 
a  "spinal  dog."  Now,  in  this  animal,  the  abdomen  and 
hind  extremities  had  no  direct  nerve  connection  with  the 
brain.  In  this  dog,  continuous  severe  trauma  of  the  ab- 
dominal viscera  and  of  the  hind  extremities  lasting  for  four 

*  Since  the  presentation  of  this  paper,  novocain  has  been  substituted  for 
cocain  in  operations  under  anoci-association. 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS      5 


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PHYLOGENETIC    ASSOCIATION    AND    MEDICAL   PROBLEMS      7 


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8  THE    EMOTIONS 

hours  was  accompanied  by  but  slight  change  in  either  the 
circulation  or  in  the  respiration,  and  by  no  microscopic 
alteration  of  the  brain-cells  (Fig.  1).  Judging  from  a  large 
nurnber  of  experiments  on  normal  dogs  under  ether,  such  an 
amount  of  trauma  would  have  caused  not  only  complete 
physiologic  exhaustion  of  the  brain,  but  also  morphologic 
alterations  of  all  of  the  brain-cells  and  the  physical  destruc- 
tion of  many  (Fig.  2).  We  must,  therefore,  conclude  that, 
although  ether  anesthesia  produces  unconsciousness,  it 
apparently  protects  none  of  the  brain-cells  against  exhaustion 
from  the  trauma  of  surgical  operations ;  ether  is,  so  to  speak, 
but  a  veneer.  Under  nitrous  oxid  anesthesia  there  is  approxi- 
mately only  one-fourth  as  much  exhaustion  as  is  produced 
by  equal  trauma  under  ether  (Fig.  3).  We  must  conclude, 
therefore,  either  that  nitrous  oxid  protects  the  brain-cells 
against  trauma  or  that  ether  predisposes  the  brain-cells  to 
exhaustion  as  a  result  of  trauma.  With  these  premises  let 
us  now  inquire  into  the  cause  of  this  exhaustion  of  the  brain- 
cells. 

The  Catise  of  the  Exhaustion  of  the  Brain-cells  as  a  Result  of 
Trauma    of    Various   Parts    of    the    Body   under   Inhalation 

Anesthesia 

Numerous  experiments  on  animals  to  determine  the  effect 
of  ether  anesthesia  per  se,  i.  e.,  ether  anesthesia  without 
trauma,  showed  that,  although  certain  changes  were  pro- 
duced, these  included  neither  the  physiologic  exhaustion 
nor  the  alterations  in  the  brain-cells  which  are  characteristic 
of  the  effects  of  trauma.  On  turning  to  the  study  of  trauma, 
we  at  once  found  in  the  behavior  of  individuals  as  a  whole 
under  deep  and  under  light  anesthesia  the  clue  to  the  cause 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS       9 

of  the  discharge  of  energy,  of  the  consequent  physiologic 
exhaustion,  and  of  the  morphologic  changes  in  the  brain-cells. 

If,  in  the  course  of  abdominal  operations,  rough  manipu- 
lations of  the  parietal  peritoneum  be  made,  there  will  be 
frequently  observed  a  marked  increase  in  the  respiratory 
rate  and  an  increase  in  the  expiratory  force  which  may  be 
marked  by  the  production  of  an  audible  expiratory  groan. 
Under  light  ether  anesthesia,  severe  manipulations  of  the 
peritoneum  often  cause  such  vigorous  contractions  of  the 
abdominal  muscles  that  the  operator  is  greatly  hindered  in 
his  work. 

Among  the  unconscious  responses  to  trauma  under  ether 
anesthesia  are  purposeless  moving,  the  withdrawal  of  the 
injured  part,  and,  if  the  anesthesia  be  sufficiently  light  and 
the  trauma  sufficiently  strong,  there  may  be  an  effort  toward 
escape  from  the  injury.  In  injury  under  ether  anesthesia 
every  grade  of  response  may  be  seen,  from  the  slightest 
change  in  the  respiration  or  in  the  blood-pressure  to  a  vigor- 
ous defensive  struggle."  As  to  the  purpose  of  these  subcon- 
scious movements  in  response  to  injury,  there  can  be  no 
doubt — they  are  efforts  to  escape  from  the  injury. 

Picture  what  would  be  the  result  of  a  formidable  ab- 
dominal operation  extending  over  a  period  of  half  an  hour 
or  more  on  an  unanesthetized  human  patient,  during  which 
extensive  adhesions  had  been  broken  up,  or  a  large  tumor 
dislodged  from  its  bed!  In  such  a  case,  would  not  the  ner- 
vous system  discharge  its  energy  to  the  utmost  in  efforts 
to  escape  from  the  injury,  and  would  not  the  patient  suffer 
complete  exhaustion?  If  the  traumata  under  inhalation 
anesthesia  are  sufficiently  strong  and  are  repeated  in  suffi- 
cient numbers,  the  brain-cells  are  finally  deprived  of  their 


10 


THE    EMOTIONS 


dischargeable  nervous  energy  and  become  exhausted  just 
as  exhaustion  follows  such  strenuous  and  prolonged  muscular 
exertion  as  is  seen  in  endurance  tests.     Whether  the  energy 


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12  THE    EMOTIONS 

and  in  exhaustion  from  pure  fear  (Fig.  5),  the  resultant 
general  functional  weakness  is  similar — in  each  case  a  certain 
length  of  time  is  required  to  effect  recovery,  and  in  each  there 
are  morphologic  changes  in  the  brain-cells.  It  is  quite  clear 
that  in  each  of  these  cases  the  altered  function  and  form  of 
the  brain-cells  are  due  to  an  excessive  discharge  of  nervous 
energy.  This  brings  us  to  the  next  question:  What  deter- 
mines the  discharge  of  energy  as  a  result  of  trauma  with  or 
without  inhalation  anesthesia? 

The  Cause  of  the  Discharge  of  Nervous  Energy  as  a  Result  of 
Trauma    under    Inhalation    Anesthesia    and    under    Normal 

Conditions 

I  looked  into  this  problem  from  many  viewpoints  and  there 
seemed  to  be  no  solution  until  it  occurred  to  me  to  seek  the 
explanation  in  certain  of  the  postulates  which  make  up  the 
doctrine  of  evolution.  I  realize  fully  the  difficulty  and  the 
danger  in  attempting  to  reach  the  generalization  which  I 
shall  make  later  and  in  the  hypothesis  I  shall  propose,  for 
there  is,  of  course,  no  direct  final  proof  of  the  truth  of  even 
the  doctrine  of  evolution.  It  is  idle  to  consider  any  experi- 
mental research  into  the  cause  of  phenomena  that  have 
developed  by  natural  selection  during  millions  of  years. 
Nature  herself  has  made  the  experiments  on  a  world-wide 
scale  and  the  data  are  before  us  for  interpretation.  Dar- 
win could  do  no  more  than  to  collect  all  available  facts  and 
then  to  frame  the  hypothesis  by  which  the  facts  were  best 
harmonized.  Sherrington,  that  masterly  physiologist,  in 
his  volume  entitled  "The  Integrative  Action  of  the  Nervous 
System,"  shows  clearly  how  the  central  nervous  system  was 
built  up  in  the  process  of  evolution.     Sherrington  has  made 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    13 

free  use  of  Darwin's  doctrine  in  explaining  physiologic 
functions,  just  as  anatomists  have  extensively  utilized  it 
in  the  explanation  of  the  genesis  of  anatomic  forms.  I 
shall  assume,  therefore,  that  the  discharge  of  nervous  energy 
is  accomplished  by  the  application  of  the  laws  of  inherit- 
ance and  association,  and  I  conclude  that  this  hypothesis 
will  explain  many  clinical  phenomena.  I  shall  now  present 
such  evidence  in  favor  of  this  hypothesis  as  time  and  my 
limitations  will  admit,  after  which  I  shall  point  out  certain 
clinical  facts  that  may  be  explained  by  this  hypothesis. 

According  to  the  doctrine  of  evolution,  every  function  owes 
its  origin  to  natural  selection  in  the  struggle  for  existence. 
In  the  lower  and  simpler  forms  of  animal  life,  indeed,  in  our 
human  progenitors  as  well,  existence  depended  principally 
upon  the  success  with  which  three  great  purposes  were 
achieved:  (1)  Self-defense  against  or  escape  from  enemies; 
(2)  the  acquisition  of  food;  and  (3)  procreation;  and  these 
were  virtually  the  only  purposes  for  which  nervous  energy 
was  discharged.  In  its  last  analysis,  in  a  biologic  sense,  this 
statement  holds  true  of  man  today.  Disregarding  for  the 
present  the  expenditure  of  energy  for  procuring  food  and 
for  procreation,  let  us  consider  the  discharge  of  energy  for 
self-preservation.  The  mechanisms  for  self-defense  which 
we  now  possess  were  developed  in  the  course  of  vast  periods 
of  time  through  innumerable  intermediary  stages  from  those 
possessed  by  the  lowest  forms  of  life.  One  would  suppose, 
therefore,  that  we  must  now  be  in  possession  of  mechanisms 
which  still  discharge  energy  on  adequate  stimulation,  but 
which  are  not  suited  to  our  present  needs.  We  shall  point 
out  some  examples  of  such  unnecessary  mechanisms.  As 
Sherrington  has  stated,  our  skin,  in  which  are  implanted 


14  THE    EMOTIONS 

many  receptors  for  receiving  specific  stimuli  which  are  trans- 
mitted to  the  brain,  is  interposed  between  ourselves  and 
the  environment  in  which  we  are  immersed.  When  these 
stimuli  reach  the  brain,  there  is  a  specific  response,  prin- 
cipally in  the  form  of  muscular  action.  Now,  each  receptor 
can  be  adequately  stimulated  only  by  the  particular  factor 
or  factors  in  the  environment  which  created  the  necessity 
for  the  existence  of  that  receptor.  Thus  there  have  arisen 
receptors  for  touch,  for  temperature,  for  pain,  etc.  The 
receptors  for  pain  have  been  designated  nociceptors  (nocuous 
or  harmful)  by  Sherrington. 

On  the  basis  of  natural  selection,  nociceptors  could  have 
developed  in  only  those  regions  of  the  body  which  have  been 
exposed  to  injury  during  long  periods  of  time.  On  this 
ground  the  finger,  because  it  is  exposed,  should  have  many 
nociceptors,  while  the  brain,  though  the  most  important 
organ  of  the  body,  should  have  no  nociceptors  because, 
during  a  vast  period  of  time,  it  has  been  protected  by  a  skull. 
Realizing  that  this  point  is  a  crucial  one.  Dr.  Sloan  and  I 
made  a  series  of  careful  experiments.  The  cerebral  hemi- 
spheres of  dogs  were  exposed  by  removing  the  skull  and  dura 
under  ether  and  local  anesthesia.  Then  various  portions 
of  the  hemispheres  were  slowly  but  completely  destroyed 
by  rubbing  them  with  pieces  of  gauze.  In  some  instances 
a  hemisphere  was  destroyed  by  burning.  In  no  case  was 
there  more  than  a  slight  response  of  the  centers  governing 
circulation  and  respiration,  and  no  morphologic  change  was 
noted  in  an  histologic  study  of  the  brain-cells  of  the  unin- 
jured hemisphere.  The  experiment  was  as  completely 
negative  as  were  the  experiments  on  the  "spinal  dog." 
Clinically    I   have    confirmed   these    experimental   findings 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    15 

when  I  have  explored  the  brains  of  conscious  patients  with 
a  probe  to  determine  the  presence  of  brain  tumors.  Such 
explorations  elicited  neither  pain  nor  any  evidence  of  altered 
physiologic  functions.  The  brain,  therefore,  contains  no 
mechanism — no  nociceptors — the  direct  stimulation  of 
which  can  cause  a  discharge  of  nervous  energy  in  a  self- 
defensive  action.  That  is  to  say,  direct  injury  of  the  brain 
can  cause  no  purposeful  nerve-muscular  action,  while  direct 
injury  of  the  finger  does  cause  purposeful  nerve-muscular 
action.  In  like  manner,  the  deeper  portions  of  the  spinal 
region  have  been  .sheltered  from  trauma  and  they,  too,  show 
but  little  power  of  causing  a  discharge  of  nervous  energy 
on  receiving  trauma.  The  various  tissues  and  organs  of  the 
body  are  differently  endowed  with  injury  receptors — the 
nociceptors  of  Sherrington.  The  abdomen  and  chest  when 
traumatized  stand  first  in  their  facility  for  causing  the  dis- 
charge of  nervous  energy,  i.  e.,  they  stand  first  in  shock  pro- 
duction. Then  follow  the  extremities,  the  neck,  and  the  back. 
It  is  an  interesting  fact  also  that  different  types  of  trauma 
elicit  different  responses  as  far  as  the  consequent  discharge 
of  energy  is  concerned. 

Because  it  is  such  a  commonplace  observation,  one  scarcely 
realizes  the  importance  of  the  fact  that  clean-cut  wounds 
inflicted  by  a  razor-like  knife  cause  the  least  reaction,  while 
a  tearing,  crushing  trauma  causes  the  greatest  response. 
It  is  a  suggestive  fact  that  the  greatest  shock  is  produced 
by  any  technic  which  imitates  the  methods  of  attack  and  of 
slaughter  used  by  the  carnivora.  In  the  course  of  evolution, 
injuries  thus  produced  may  well  have  been  the  predominating 
type  of  traumata  to  which  our  progenitors  were  subjected. 

In  one  particular  respect  there  is  an  analogy  between  the 


16  THE    EMOTIONS 

response  to  trauma  of  some  parts  of  the  body  of  the  indi- 
viduals of  a  species  susceptible  to  shock  and  the  response  to 
trauma  of  the  individuals  in  certain  other  great  divisions  of 
the  animal  kingdom.  Natural  selection  has  protected  the 
crustaceans  against  their  enemies  by  protective  armor,  e.  g., 
the  turtle  and  the  armadillo ;  to  the  birds,  it  has  given  sharp 
eyes  and  wings,  as,  for  instance,  the  wild  goose;  to  another 
species — the  skunk — it  has  given  a  noisome  odor  for  its 
protection.  The  turtle,  protected  by  its  armor  against 
trauma,  is  in  a  very  similar  position  to  that  of  the  sheltered 
brain  of  man;  and,  like  the  brain,  the  turtle  does  not  respond 
to  trauma  by  an  especially  active  self-protective  nerve- 
muscular  response,  but  merely  withdraws  its  head  and  legs 
within  the  armored  protection.  It  is  proverbially  difficult 
to  exhaust  or  to  kill  this  animal  by  trauma.  The  brain  and 
other  phylogenetically  sheltered  parts  likewise  give  no  ex- 
hausting self-protective  nerve-muscular  response  to  trauma. 
The  skunk  is  quite  effectively  protected  from  violence  by  its 
peculiar  odor.  This  is  indicated  not  only  by  the  protective 
value  of  the  odor  itself,  but  also  by  the  fact  that  the  skunk 
has  no  efficient  nerve-muscular  mechanism  for  escape  or 
defense;  it  can  neither  run  fast  nor  can  it  climb  a  tree. 
Moreover,  in  encounters  it  shows  no  fear  and  backs  rather 
than  runs.  The  armadillo  rolls  itself  into  a  ball  for  defense. 
On  these  premises  we  should  conclude  that  the  turtle,  the 
armadillo,  and  the  skunk  have  fewer  nociceptors  than  has 
a  dog  or  man,  and  that  they  would  show  less  response  to 
trauma.  In  two  carefully  conducted  experiments  on  skunks 
and  two  on  armadillos  (an  insufficient  number)  the  energy 
discharged  in  response  to  severe  and  protracted  trauma  of 
the  abdominal  viscera  was  very  much  less  than  in  similar 


PHYLOGEXETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    17 

experiments  on  dogs,  opossums,  pigs,  sheep,  and  rabbits. 
It  was  indeed  relatively  difficult  to  exhaust  the  skunks  and 
armadillos  by  trauma.  These  experiments  are  too  few  to 
be  conclusive,  but  thev  are  of  some  value  and  furnish  an 


Fig.  6. — Tiger  and  Cobra. 
The  attitude  of  each  animal  is  that  of  watchful  approach  rather  than  of 
fear,  an  emotion  unfelt  by  the  cobra  guarded  by  his  venom,  or  by  the  tiger 
conscious  of  his  strong  and  powerful  equipment  for  defense. 


excellent  lead.  It  seems  more  than  a  coincidence  that 
proneness  to  fear,  distribution  of  nociceptors,  and  suscepti- 
bility to  shock  go  hand-in-hand  in  these  comparative  ob- 
servations (Figs.  6,  7,  and  8). 


18 


THE    EMOTIONS 


The  discharge  of  energy  caused  by  an  adequate  mechanical 
stimulation  of  the  nociceptors  is  best  explained  in  accordance 
with  the  law  of  phylogenetic  association.     That  is,  injuries 


Fig.  7. — Contest  Between  a  Deer  and  a  Dog. 

Compare  the  intense  stimulation  and  fearful  excitement  manifested  by  these 

animals  with  the  calm  control  of  the  animals  in  Fig.  6. 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    19 

awaken  those  reflex  actions  which  by  natural  selection  have 
been  developed  for  the  purpose  of  self-protection.  Ade- 
quate stimulation  of  the  nociceptors  for  pain  is  not  the 
onh'  means  by  which  a  discharge  of  nervous  energy  is  caused. 


A  B 

Fig.  S. — The  Finish  of  a  Race. 
The  contrast  between  animals  in  Figs.  6  and  7  finds  its  analogy  in  a  com- 
parison of  these  runners — A,  poorly  equipped  by  training  and  fearful  of  the  re- 
sult, shows  every  evidence  of  exhaustion;    while  B,  confident  in  the  strength 
given  by  superior  training,  wins  the  race  with  ease. 


Nervous  energy  may  be  discharged  also  by  adequate  stimu- 
lation of  the  various  ticklish  regions  of  the  body;  the  entire 
skin  surface  of  the  body  contains  delicate  ticklish  receptors. 
These  receptors  are  closely  related  to  the  nociceptors  for 


20  THE    EMOTIONS 

pain,  and  their  adequate  stimulation  by  an  insect-like  touch 
causes  a  discharge  of  energy, — a  nerve-muscular  reaction, — 
resembling  that  developed  for  the  purpose  of  brushing  off 
insects.  This  reflex  is  similar  to  the  scratch  reflex  in  the 
dog.  The  discharge  of  energy  is  almost  wholly  independent 
of  the  will  and  is  a  self-protective  action  in  the  same  sense 
as  is  the  response  to  pain  stimuli.  The  ear  in  man  and  in 
animals  is  acutely  ticklish,  the  adequate  stimulus  being 
any  foreign  body,  especially  a  buzzing,  insect-like  contact. 
The  discharge  of  nervous  energy  in  horses  and  in  cattle  on 
adequate  stimulation  of  the  ticklish  receptors  of  the  ear  is  so 
extraordinary  that  in  the  course  of  evolution  it  must  have 
been  of  great  importance  to  the  safety  of  the  animal.  A 
similar  ticklish  zone  guards  the  nasal  chambers,  the  discharge 
of  energy  here  taking  a  form  which  effectively  dislodges 
the  foreign  body.  The  larynx  is  exquisitely  ticklish,  and, 
in  response  to  any  adequate  stimulus,  energy  is  discharged 
in  the  production  of  a  vigorous  cough.  The  mouth  and 
pharynx  have  active  receptors  which  cause  the  rejection  of 
noxious  substances.  The  conjunctival  reflex,  though  not 
classed  as  ticklish,  is  a  most  efficient  self-protective  reflex. 
I  assume  that  there  is  no  doubt  as  to  the  relation  between  the 
adequate  stimuli  and  the  nerve-muscular  response  of  the 
various  ticklish  receptors  of  the  surface  of  the  skin,  of  the 
ear,  the  nose,  the  eye,  and  the  larynx.  These  mechanisms 
were  developed  by  natural  selection  as  protective  measures 
against  the  intrusion  of  insects  and  foreign  bodies  into  regions 
of  great  importance.  The  discharge  of  energy  in  these 
instances  is  in  accordance  with  the  laws  of  inheritance  and 
association.  The  other  ticklish  points  which  are  capable  of 
discharging  vast  amounts  of  energy  are  the  lateral  chest-wall, 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    21 

the  abdomen,  the  loins,  the  neck,  and  the  soles  of  the  feet. 
The  type  of  adequate  stmiuli  of  the  soles  of  the  feet,  the  dis- 


FiG.  9. — Contest  Between  Ant-bear  and  Puma. 
This  shows  the  attack  with  teeth  and  claws  upon  unprotected  parts,  and 
illustrates  the  method  by  which  deep,  tickhsh  points  were  developed  and  why 
trauma  of  these  parts  produces  the  greatest  shock. 


tribution  of  the  ticklish  points  upon  them,  and  the  associ- 
ated response,  leave  no  doubt  that  these  ticklish  points  were 


22  THE    EMOTIONS 

long  ago  established  as  a  means  of  protection  from  injury. 
Under  present  conditions  they  are  of  little  value  to  man. 

The  adequate  stimulus  for  the  ticklish  points  of  the  ribs, 
the  loins,  the  abdomen,  and  the  neck  is  deep  isolated  pres- 
sure, probably  the  most  adequate  being  pressure  by  a  tooth- 
shaped  body.  The  response  to  tickling  in  these  regions  is 
actively  and  obviously  self-defensive.     The  horse  discharges 


Fig.  10. — Bear  Cubs  at  Play. 
They  are  clawing  and  biting  each  other  in  ticklish  points  and  thus  recapitu- 
lating ancestral  battles.     (Photo  by  Underwood  and  Underwood,  N.  Y.) 

energy  in  the  form  of  a  kick;  the  dog  wriggles  and  makes  a 
counter-bite;  the  man  makes  efforts  at  defense  and  escape. 
There  is  strong  evidence  that  the  deep  ticklish  points  of  the 
body  were  developed  through  vast  periods  of  fighting  with 
teeth  and  claws  (Fig.  9).  Even  puppies  at  play  bite  each 
other  in  their  ticklish  points  and  thus  give  a  recapitulation 
of  their  ancestral  battles  and  of  the  real  battles  to  come  (Fig. 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    23 

10).  The  mere  fact  that  animals  fight  effectively  in  the  dark 
and  always  according  to  the  habit  of  their  species  supports 
the  belief  that  the  fighting  of  animals  is  not  an  intellectual 
but  a  reflex  process.  There  are  no  rules  which  govern  the 
conduct  of  a  fight  between  animals.  The  events  follow  each 
other  with  such  kaleidoscopic  rapidity  that  the  process  is 
but  a  series  of  automatic  stimulations  and  physiologic  reac- 
tions. Whatever  their  significance,  therefore,  it  is  certain 
that  man  did  not  come  either  accidentally  or  without  purpose 
into  possession  of  the  deep  ticklish  regions  of  his  chest  and 
abdomen.  Should  any  one  doubt  the  vast  power  that  ade- 
quate stimulation  of  these  regions  possesses  in  causing  the 
discharge  of  energy,  let  him  be  bound  hand  and  foot  and 
vigorously  tickled  for  an  hour.  What  would  happen?  He 
would  be  as  completely  exhausted  as  though  he  had  experi- 
enced a  major  surgical  operation  or  had  run  a  Marathon  race. 
A  close  analogy  to  the  reflex  process  in  the  fighting  of 
animals  is  shown  in  the  role  played  by  the  sexual  receptors 
in  conjugation.  Adequate  stimulation  of  either  of  these  two 
distinct  groups  of  receptors,  the  sexual  and  the  noci,  causes 
specific  behavior — the  one  toward  embrace,  the  other  to- 
ward repulsion.  Again,  one  of  the  most  peremptory  causes 
of  the  discharge  of  energy  is  that  due  to  an  attempt  to  ob- 
struct forcibly  the  mouth  and  the  nose  so  that  asphyxia 
is  threatened.  Under  such  conditions  neither  friend  nor 
foe  is  trusted,  and  a  desperate  struggle  for  air  ensues.  It  will 
be  readily  granted  that  the  reactions  to  prevent  suffocation 
were  established  for  the  purpose  of  self-preservation,  but  the 
discharge  of  nerve-muscular  energy  to  this  particular  end 
is  no  more  specific  and  no  more  shows  adaptive  qualities 
than  do  the  preceding  examples.     Even  the  proposal  to  bind 


24  THE    EMOTIONS 

one  down  hand  and  foot  excites  resentment,  a  feeling  origin- 
ally suggested  by  the  need  for  self-preservation.  No  patient 
views  with  equanimity  the  application  of  shackles  as  a 
preparation  for  anesthesia.    . 

We  have  now  considered  some  of  the  causes  of  those  dis- 
charges of  nervous  energy  which  result  from  various  types 
of  harmful  physical  contact,  and  have  referred  to  the  analo- 
gous, though  antithetical,  response  to  the  stimulation  of  the 
sexual  receptors.  The  response  to  the  adequate  stimuli 
of  each  of  the  several  receptors  is  a  discharge  of  nerve- 
muscular  energy  of  a  specific  type ;  that  is,  there  is  one  type 
of  response  for  the  ear,  one  for  the  larynx,  one  for  the  pharynx, 
another  for  the  nose,  another  for  the  eye,  another  for  the 
deep  ticklish  points  of  the  chest  and  the  abdomen,  quite 
another  for  the  delicate  tickling  of  the  skin,  and  still  another 
type  of  response  to  sexual  stimuli. 

According  to  Sherrington,  a  given  receptor  has  a  low 
threshold  for  only  one,  its  own  specific  stimulus,  and  a  high 
threshold  for  all  others;  that  is,  the  doors  that  guard  the 
nerve-paths  to  the  brain  are  opened  only  when  the  proper 
password  is  received.  According  to  Sherrington's  law,  the 
individual  as  a  whole  responds  to  but  one  stimulus  at  a 
time,  that  is,  only  one  stimulus  occupies  the  nerve-paths 
which  carry  the  impulses  as  a  result  of  which  acts  are  per- 
formed, i.  e.,  the  final  common  path.  As  soon  as  a  stronger 
stimulus  reaches  the  brain  it  dispossesses  whatever  other 
stimulus  is  then  occupying  the  final  common  path — the  path 
of  action.  The  various  receptors  have  a  definite  order  of 
precedence  over  each  other  (Sherrington).  For  example, 
the  impulse  from  the  delicate  ticklish  points  of  the  skin, 
whose  adequate  stimulus  is  an  insect-like  contact,  could  not 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    25 

successfully  compete  for  the  final  common  path  with  the 
stimulus  of  a  nociceptor.  The  stimulus  of  a  fly  on  the  nose 
would  be  at  once  superseded  by  the  crushing  of  a  finger. 
In  quick  succession  do  the  various  receptors  (Sherrington) 
occupy  the  final  common  path,  but  each  stimulus  is  for  the 
time  the  sole  possessor,  hence  the  nervous  system  is  inte- 
grated (connected)  to  act  as  a  whole.  Each  individual  at 
every  moment  of  life  has  a  limited  amount  of  dischargeable 
nervous  energy.  This  energy  is  at  the  disposal  of  any 
stimulus  that  obtains  possession  of  the  final  common  path, 
and  results  in  the  performance  of  an  act.  Each  discharge 
of  energy  is  subtracted  from  the  sum  total  of  stored  energy 
and,  whether  the  subtractions  are  made  by  the  excitation  of 
nociceptors  by  trauma,  by  tickling,  by  fighting,  by  fear,  by 
flight,  or  by  the  excitation  of  sexual  receptors,  by  any  of 
these  singly  or  in  combination  with  others,  the  sum  total 
of  the  expenditure  of  energy,  if  large  enough,  produces  ex- 
haustion. Apparently  there  is  no  distinction  between  that 
state  of  exhaustion  which  is  due  to  the  discharge  of  nervous 
energy  in  response  to  trauma  and  that  due  to  other  causes. 
The  manner  of  the  discharge  of  energy  is  specific  for  each 
type  of  stimulation.  On  this  conception,  traumatic  shock 
takes  its  place  as  a  natural  phenomenon  and  is  divested  of 
its  mask  of  mystery. 

The  Discharge  of  Energy  through  Stimulation  of  the  Distance 
Receptors,  or  through  Representation  of  Injury  (Psychic) 

We  will  now  turn  from  the  discussion  of  the  discharge  of 
nervous  energy  by  mechanical  stimuli  to  the  discharge  of 
energy  through  mental  perception.  Phylogenetic  association 
may   result    from    stimulation    of    the    distance    receptors 


26  THE    EMOTIONS 

through  sight,  hearing,  smell,  or  by  a  representation  of 
physical  experiences,  as  well  as  from  physical  contact.  The 
effect  upon  the  organism  of  the  representation  of  injury 
or  of  the  perception  of  danger  through  the  distance  receptors 
is  designated  fear.  Fear  is  as  widely  distributed  in  nature 
as  is  its  cause,  that  is,  fear  is  as  widely  distributed  as  injury. 
Animals  under  the  stimulus  of  fear,  according  to  W.  T.  Horn- 
aday,  not  only  may  exhibit  preternatural  strength,  but  also 
may  show  strategy  of  the  highest  order,  a  strategy  not  seen 
under  the  influence  of  a  lesser  stimulus.  In  some  animals 
fear  is  so  intense  that  it  defeats  escape;  this  is  especially 
true  in  the  case  of  birds  in  the  presence  of  snakes.  The 
power  of  flight  has  endowed  the  bird  with  an  easy  means  of 
escape  from  snakes,  especially  when  the  encounter  is  in  the 
tops  of  trees.  Here  the  snake  must  move  cautiously,  else 
he  will  lose  his  equilibrium;  his  method  of  attack  is  by 
stealth.  When  the  snake  has  stalked  its  prey,  the  bird  is 
often  so  overcome  by  fear  that  it  cannot  fly  and  so  becomes 
an  easy  victim  (Fig.  11).  The  phenomena  of  fear  are 
described  by  Darwin  as  follows: 

''Fear  is  often  preceded  by  astonishment,  and  is  so  near 
akin  to  it  that  both  lead  to  the  senses  of  sight  and  hearing 
being  instantly  aroused.  In  both  cases  the  eyes  and  mouth 
are  widely  opened  and  the  eyebrows  raised.  The  frightened 
man  at  first  stands  like  a  statue,  motionless  and  breathless, 
or  crouches  down  as  if  instinctively  to  escape  observation. 
The  heart  beats  quickly  and  violently,  so  that  it  palpitates 
or  knocks  against  the  ribs.  *  *  *  That  the  skin  is 
much  affected  under  the  sense  of  great  fear  we  see  in  the 
marvelous  and  inexplicable  manner  in  which  perspiration 
immediately  exudes  from  it.     This  exudation  is  all  the  more 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL   PROBLEMS    27 

remarkable  as  the  surface  is  then  cold,  and  hence  the  term, 
'a  cold  sweat';    whereas  the  sudorific  glands  are  properly 


Fig.  11. — Bird  Charmed  by  Snake. 
Fear  so  dominates  the  bird  that  it  is  unable  to  fly. 


excited  into  action  when  the  surface  is  heated.  The  hairs 
also  on  the  skin  stand  erect,  and  the  superficial  muscles 
shiver.     In  connection  with  the  disturbed  action  of  the  heart. 


28  THE    EMOTIONS 

the  breathing  is  hurried.  The  sahvary  glands  act  imper- 
fectly; the  mouth  becomes  dry,  and  is  often  opened  and  shut. 
I  have  also  noticed  that  under  slight  fear  there  is  a  strong 
tendency  to  yawn.  One  of  the  best-marked  symptoms  is 
the  trembling  of  all  the  muscles  of  the  body;  and  this  is 
often  first  seen  in  the  lips.  From  this  cause,  and  from  the 
dryness  of  the  mouth,  the  voice  becomes  husky  and  indis- 
tinct, or  may  altogether  fail.  *  *  *  ^s  fg^r  increases 
into  agony  of  terror,  we  behold,  as  under  all  violent  emotions, 
diversified  results.  The  heart  beats  wildly,  or  may  fail  to 
act  and  faintness  ensues;  there  is  death-like  pallor;  the 
breathing  is  labored;  the  wings  of  the  nostrils  are  widely 
dilated;  'there  is  a  gasping  and  convulsive  motion  of  the 
lips,  a  tremor  on  the  hollow  cheek,  a  gulping  and  catching 
of  the  throat';  the  uncovered  and  protruding  eyeballs  are 
fixed  on  the  object  of  terror;  or  they  may  roll  restlessly 
from  side  to  side.  *  *  *  The  pupils  are  said  to  be 
enormously  dilated.  All  the  muscles  of  the  body  may  be- 
come rigid,  or  may  be  thrown  into  convulsive  movements. 
The  hands  are  alternately  clenched  and  opened,  often  with 
a  twitching  movement.  The  arms  may  be  protruded,  as 
if  to  avert  some  dreadful  danger,  or  may  be  thrown  wildly 
over  the  head.  *  *  *  i^  other  cases  there  is  a  sudden 
and  uncontrollable  tendenc};^  to  headlong  flight;  and  so 
strong  is  this  that  the  boldest  soldiers  may  be  seized  with  a 
sudden  panic.  As  fear  rises  to  an  extreme  pitch,  the  dread- 
ful scream  of  terror  is  heard.  Great  beads  of  sweat  stand 
on  the  skin.  All  the  muscles  of  the  body  are  relaxed. 
Utter  prostration  soon  follows,  and  the  mental  powers  fail. 
The  intestines  are  affected.  The  sphincter  muscles  cease  to 
act  and  no  longer  retain  the  contents  of  the  body.     *     *     * 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    29 

Men,  during  nmnberless  generations,  have  endeavored  to 
escape  from  their  enemies  or  danger  by  headlong  flight,  or 
by  violently  struggling  with  them ;  and  such  great  exertions 
will  have  caused  the  heart  to  beat  rapidly,  the  breathing 


Fig.  12. — Photo  Showing  Facies  of  Person  Obsessed  by  Fear. 


to  be  hurried,  the  chest  to  heave,  and  the  nostrils  to  be 
dilated.  As  these  exertions  have  often  been  prolonged  to 
the  last  extremity,  the  final  result  will  have  been  utter  pros- 
tration, pallor,  perspiration,  trembling  of  all  the  muscles, 
or  their  complete  relaxation.     And  now,  whenever  the  emo- 


30  THE    EMOTIONS 

tion  of  fear  is  strongly  felt,  though  it  may  not  lead  to  any 
exertion,  the  same  results  tend  to  reappear,  through  the  force 
of  inheritance  and  association"*  (Fig.  12). 

In  an  experimental  research,  we  found  evidence  that 
the  physiologic  phenomena  of  fear  have  a  physical  basis. 
This  evidence  is  found  in  the  morphologic  alterations  in  the 
brain-cells,  which  are  similar  to  those  observed  in  certain 
stages  of  surgical  shock  and  in  fatigue  from  muscular  exer- 
tion (Figs.  2,  4,  5,  and  13).  For  the  present,  we  shallassume 
that  fear  is  a  representation  of  trauma.  Because  fear  was 
created  by  trauma,  fear  causes  a  discharge  of  the  energy  of 
the  nervous  system  by  the  law  of  phylogenetic  association. 
The  almost  universal  fear  of  snakes,  of  blood,  and  of  death 
and  dead  bodies  may  have  such  a  phylogenetic  origin.  It 
was  previously  stated  that  under  the  stimulus  of  fear  animals 
show  preternatural  strength.  An  analysis  of  the  phenomena 
of  fear  shows  that,  as  far  as  can  be  determined,  all  the 
functions  of  the  body  requiring  the  expenditure  of  energy, 
and  which  are  of  no  direct  assistance  in  the  effort  toward 
self-preservation,  are  suspended.  In  the  voluntary  expendi- 
ture of  muscular  energy,  as  in  the  chase,  the  suspension  of 
other  functions  is  by  no  means  so  complete.  Fear  and 
trauma  may  drain  to  the  last  dreg  the  dischargeable  nervous 
energy,  and,  therefore,  the  greatest  possible  exhaustion  may 
be  produced  by  fear  and  trauma. 

Stfmmation 
In  the  discharge  of  energy,  summation  plays  an  important 
role.     Summation  is  attained  by  the  repetition  of  stimuli 
at  such  a  rate  that  each  succeeding  stimulus  is  applied  before 

*  Darwin:  Expression  of  the  Emotions  in  Man  and  Animals. 


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32  THE    EMOTIONS 

the  nerve-cells  have  returned  to  the  resting  stage  from  the 
preceding  stimulus.  If  drops  of  water  fall  upon  the  skin 
from  a  sufficient  height  to  cause  the  slightest  unpleasant 
sensation,  and  at  such  a  rate  that  before  the  effect  of  the 
stimulus  of  one  drop  has  passed  another  drop  falls  in  pre- 
cisely the  same  spot,  there  will  be  felt  a  gradually  increasing 
painful  sensation  which  finally  becomes  unbearable.  This  is 
summation  of  stimuli.  When,  for  a  long  time,  a  patient 
requires  frequent  painful  wound  dressings,  there  is  a  gradual 
increase  in  the  acuteness  of  the  pain  of  the  receptors.  This  is 
caused  by  summation.  In  a  larger  sense,  the  entire  be- 
havior of  the  individual  gives  considerable  evidence  of 
summation,  e.  g.,  in  the  training  of  athletes,  the  rhythmic 
discharge  of  muscular  energy  at  such  intervals  that  the 
resting  stage  is  not  reached  before  a  new  exercise  is  given 
results  in  a  gradual  ascent  in  efficiency  until  the  maximum 
is  reached.  This  is  summation,  and  summation  plays  a 
large  role  in  the  development  of  both  normal  and  pathologic 
phenomena. 

We  have  now  pointed  out  the  manner  in  which  at  least  a 
part  of  the  nervous  energy  of  man  may  be  discharged.  The 
integrative  action  of  the  nervous  system  and  the  discharge 
of  nervous  energy  by  phylogenetic  association  may  be 
illustrated  by  their  analogy  to  the  action  of  an  electric 
automobile.  The  electric  automobile  is  composed  of  four 
principal  parts:  The  motor  and  the  wheels  (the  muscular 
system  and  the  skeleton) ;  the  cells  of  the  battery  containing 
stored  electricity  (brain-cells,  nervous  energy);  the  con- 
troller, which  is  connected  with  the  cells  by  wiring  (the  re- 
ceptors and  the  nerve-fibers) ;  and  an  accelerator  for  increas- 
ing the  electric  discharge  (thyroid  gland?).     The  machine 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    33 

is  SO  constructed  that  it  acts  as  a  whole  for  the  accomphsh- 
ment  of  a  single  purpose.  When  the  controller  is  adjusted 
for  going  ahead  (adequate  stimulus  of  a  receptor),  then  the 
conducting  paths  (the  final  common  path)  for  the  accom- 
plishment of  that  purpose  are  all  open  to  the  flow  of  the  cur- 
rent from  the  battery,  and  the  vehicle  is  integrated  to  go 
ahead.  It  spends  its  energy  to  that  end  and  is  closed  to 
all  other  impulses.  Wlien  the  controller  is  set  for  reverse, 
by  this  adequate  stimulus  the  machine  is  integrated  to  back, 
and  the  battery  is  closed  to  all  other  impulses.  Whether 
integrated  for  going  forward  or  backward,  if  the  battery 
be  discharged  at  a  proper  rate  until  exhausted,  the  cells, 
though  possessing  no  more  power  (fatigue),  have  sustained 
no  further  impairment  of  their  elements  than  that  of  normal 
wear  and  tear.  Furthermore,  they  may  be  restored  to  nor- 
mal activity  by  recharging  (rest).  If  the  vehicle  be  placed 
against  a  stone  wall,  and  the  controller  be  placed  at  high- 
speed (trauma  and  fear),  and  if  the  accelerator  be  used  as 
well  (thyroid  secretion?),  though  the  machine  will  not  move, 
not  only  will  the  battery  soon  be  exhausted,  but  the  battery 
elements  themselves  will  be  seriously  damaged  (exhaustion 
— surgical  shock). 

We  have  now  presented  some  evidence  that  nervous  energy 
is  discharged  by  the  adequate  stimulation  of  one  or  more  of 
the  various  receptors  that  have  been  developed  in  the  course 
of  evolution.  In  response  to  an  adequate  stimulus,  the  ner- 
vous system  is  integrated  for  a  specific  purpose  by  the 
stimulated  receptor,  and  but  one  stimulus  at  a  time  has 
possession  of  the  final  common  path — the  nerve  mechanisms 
for  action.  The  most  numerous  receptors  are  those  for 
harmful   contact;     these   are   the   nociceptors.     The   effect 

3 


34  THE   EMOTIONS 

of  the  adequate  stimulus  of  a  nociceptor  is  like  that  of  press- 
ing an  electric  button  that  sets  great  machinery  in  motion. 

With  this  conception,  the  human  body  may  be  likened  to  a 
musical  instrument — an  organ — the  keyboard  of  which  is 
composed  of  the  various  receptors,  upon  which  environment 
plays  the  many  tunes  of  life;  and  written  within  ourselves 
in  symbolic  language  is  the  history  of  our  evolution.  The 
skin  may  be  the  ''Rosetta  Stone"  which  furnishes  the  key. 

Anoci-association 

By  the  law  of  phylogenetic  association,  we  are  now  pre- 
pared to  make  a  practical  application  of  the  principles  of  the 
discharge  of  nervous  energy.  In  the  case  of  a  surgical  oper- 
ation, if  fear  be  excluded  and  if  the  nerve-paths  between 
the  field  of  operation  and  the  brain  be  blocked  with  cocain,* 
no  discharge  of  energy  will  be  caused  by  the  operation; 
hence  no  shock,  no  exhaustion,  can  result.  Under  such  con- 
ditions the  nervous  system  is  protected  against  noci-associa- 
tion,  resulting  from  noci-perception  or  from  an  adequate 
stimulation  of  nociceptors.  The  state  of  the  patient  in 
whom  all  noci-associations  are  excluded  can  be  described 
only  by  coining  a  new  word.  That  word  is  ''anoci-associa- 
tion" (Fig.  14). 

The  difference  between  anesthesia  and  anoci-association 
is  that,  although  inhalation  anesthesia  confers  the  beneficent 
loss  of  consciousness  and  freedom  from  pain,  it  does  not  pre- 
vent the  nerve  impulses  from  reaching  and  influencing  the 
brain,  and  therefore  does  not  prevent  surgical  shock  nor  the 
train  of  later  nervous  impairments  so  well  described  by  Mum- 
ford.     Anoci-association  excludes  fear,  pain,  shock,  and  post- 

*  See  footnote,  page  4. 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    35 

operative  neuroses.     Anoci-association  is  accomplished  by 
combining   the   special   management   of   patients    (applied 


1 


fl 


HI 


n 


Fig.  14. — Schematic  Drawing  Illustrating  Protective  Effect  of  Anoci- 
association. 
I.  Conscious  patient  in  whom  auditor}^,  visual,  olfactory,  and  traumatic 
noci-impulses  reach  the  brain. 

II.  Patient  under  inhalation  anesthesia  in  whom  only  traumatic  noci-im- 
pulses reach  the  brain. 

III.  Patient  under  complete  anoci-association:  auditory,  visual,  and  ol- 
factory impulses  are  excluded  from  the  brain  by  the  inhalation  anesthesia; 
traumatic  impulses  from  the  seat  of  injury  are  blocked  bj-  novocain. 


psychology),    morphin,    inhalation    anesthesia,    and    local 
anesthesia. 

We  have  now  presented  in  summary  much  of  the  mass  of 
experimental  and  clinical  evidence  we  have  accumulated  in 


36  THE    EMOTIONS 

support  of  our  principal  theme,  which  is  that  the  discharge 
of  nervous  energy  is  accomphshed  in  accordance  with  the 
law  of  phylogenetic  association.  If  this  point  seems  to  have 
been  emphasized  unduly,  it  is  because  we  expect  to  rear  upon 
this  foundation  a  clinical  structure.  How  does  this  hypoth- 
esis apply  to  surgical  operations? 

Prevention  of  Shock  by  the  Application  of  the  Principle  of  Anoci- 

association 

Upon  this  hypothesis  a  new  principle  in  operative  surgery 
is  founded,  i.  e.,  operation  during  the  state  of  anoci-associa- 
tion.  Assuming  that  no  unfavorable  effect  is  produced  by 
the  anesthetic  and  that  there  is  no  hemorrhage,  the  cells  of 
the  brain  cannot  be  exhausted  in  the  course  of  a  surgical 
operation  except  by  fear  or  by  trauma,  or  by  both.  Fear 
may  be  excluded  by  narcotics  and  special  management  until 
the  patient  is  rendered  unconscious  by  inhalation  anesthesia. 
Then  if,  in  addition  to  inhalation  anesthesia,  the  nerve-paths 
between  the  brain  and  the  field  of  operation  are  blocked  with 
cocain,*  the  patient  will  be  placed  in  the  beneficent  state  of 
anoci-association,  and  at  the  completion  of  the  operation 
will  be  as  free  from  shock  as  at  the  beginning.  In  so-called 
"fair  risks"  such  precautions  may  not  be  necessary,  but  in 
cases  handicapped  by  infections,  by  anemia,  by  previous 
shock,  and  by  Graves'  disease,  etc.,  anoci-association  may 
become  vitally  important. 

Graves'  Disease 
By  applying  the  principle  of  the  discharge  of  nervous 
energy   by   phylogenetic   association,    and  by  making   the 

*  See  footnote,  page  4. 


PHYLOGEXETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS     37 

additional  hypothesis  that  in  the  discharge  of  nervous  energy 
the  thyroid  gland  is  stimulated  through  the  nervous  system, 
we  can  explain  many  of  the  phenomena  of  Graves'  disease 
and  may  possibly  discover  some  of  the  factors  which  explain 
both  its  genesis  and  its  cure. 

In  the  wild  state  of  animal  life  in  which  only  the  fittest 
survive  in  the  struggle  for  existence,  every  point  of  advantage 
has  its  value.  An  animal  engaged  in  battle  or  in  a  desperate 
effort  to  escape  will  be  able  to  give  a  better  account  of  itself 
if  it  have  some  means  of  accelerating  the  discharge  of  energy 
— some  influence  like  that  of  pouring  oil  upon  the  kindling 
fire.  There  is  evidence,  though  perhaps  it  is  not  conclusive, 
that  such  an  influence  is  exerted  by  the  thyroid  gland.  In 
mjTiedema,  a  condition  characterized  by  a  lack  of  thyroid 
secretion,  there  is  dulness  of  the  reflexes  and  of  the  intellect, 
a  lowered  muscular  power,  and  generally  a  sluggish  discharge 
of  energy.  In  Graves'  disease  there  is  an  excessive  produc- 
tion of  thyroid  secretion.  In  this  disease  the  reflexes  are 
increased,  the  discharge  of  energy  is  greatlj^  facilitated,  and 
metabolism  is  at  a  maximum.  The  same  phenomena  occur 
also  after  the  administration  of  thyroid  extract  in  large  doses 
to  normal  subjects.  In  the  course  of  sexual  activities  there 
is  an  increased  action  of  the  thyroid,  which  is  indicated  by  an 
increase  in  its  size  and  vascularity.  That  in  fear  and  in 
injury  the  thyroid,  in  cases  of  Graves'  disease,  is  probably 
stimulated  to  increased  activity  is  indicated  by  the  increased 
activity  of  the  thyroid  circulation,  by  an  increase  in  the  size 
of  the  gland,  by  the  histologic  appearance  of  activity  in  the 
nuclei  of  the  cells,  and  by  an  increase  of  the  toxic  symptoms. 
Finally,  Asher  has  stated  that  electric  stimulation  of  the 
nerve  supply  of  the  thyroid  causes  an  increased  secretion. 


38  THE    EMOTIONS 

The  origin  of  many  cases  of  Graves'  disease  is  closely  associ- 
ated with  some  of  the  causes  of  the  discharge  of  nervous 
energy,  depressive  influences  especially,  such  as  nervous 
shocks,  worry  and  nervous  strain,  disappointment  in  love, 
business  reverses,  illness  and  death  of  relatives  and  friends. 
The  association  of  thyroid  activity  with  procreation  is  well 
known,  hence  the  coincidence  of  a  strain  of  overwork  or  of 
fear  with  the  sexual  development  of  maturing  girls  is  ob- 
viously favorable  to  the  incidence  of  Graves'  disease.  The 
presence  of  a  colloid  goiter  is  a  suitable  soil  for  the  develop- 
ment of  Graves'  disease,  and  I  fully  recognize  also  the  evi- 
dence that  infection  or  auto-intoxication  may  be  contribut- 
ing factors  and  must  be  assigned  their  role. 

I  have  never  known  a  case  of  Graves'  disease  to  be  caused 
by  success  or  happiness  alone,  or  by  hard  physical  labor 
unattended  by  psychic  strain,  or  to  be  the  result  of  energy 
voluntarily  discharged.  Some  cases  seem  to  have  had  their 
origin  in  overdosage  with  thyroid  extract  in  too  vigorous  an 
attempt  to  cure  a  colloid  goiter.  One  of  the  most  striking 
characteristics  of  Graves'  disease  is  the  patient's  loss  of 
control  and  his  increased  susceptibility  to  stimuli,  especially 
to  trauma  and  to  fear  and  to  the  administration  of  thyroid 
extract.  It  has  been  shown  that  the  various  causes  of  the 
discharge  of  nervous  energy  produce  alterations  in  the  ner- 
vous system  and  probably  in  the  thyroid  gland.  This  is 
especially  true  of  the  fear  stimulus,  and  has  been  clearly 
demonstrated  in  the  brains  of  rabbits  which  had  been  sub- 
jected to  fear  alone  (Fig.  13).  Of  special  interest  was  the 
effect  of  daily  fright.  In  this  case  the  brain-cells  showed  a 
distinct  change,  although  the  animal  had  been  subjected  to 
no  fear  for  twenty-four  hours  before  it  was  killed  (Fig.  13  C). 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    39 


40  THE    EMOTIONS 

Now,  a  great  distinction  between  man  and  the  lower  animals 
is  the  greater  control  man  has  acquired  over  his  actions. 
This  quality  of  control,  having  been  phylogenetically  most 
recently  acquired,  is  the  most  vulnerable  to  various  nocuous 
influences.  The  result  of  a  constant  noci-integration  may  be 
a  wearing-out  of  the  control  cells  of  the  brain.     In  a  typical 


Fig.  16. — Typical  Case  of  Exophthalmic  Goiter  showing  Characteristic 

Facies. 


case  of  Graves'  disease  a  marked  morphologic  change  in  the 
brain-cells  has  been  demonstrated  (Fig.  15).  As  has  been 
previously  stated,  the  origin  of  many  cases  of  Graves' 
disease  is  associated  with  some  noci-influence.  If  this  in- 
fluence causes  stimulation  of  both  the  brain  and  the  thyroid, 
its  excessive  action  may  cause  impairment  of  the  brain 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    41 

and  also  hyperplasia  of  the  thyroid.  As  self-control  is  im- 
paired, fear  obtains  an  ascendency  and,  pari  passu,  stimulates 
the  thyroid  still  more  actively  (Fig.  16).  Finally,  the  fear 
of  the  disease  itself  becomes  a  noci-stimulus.  As  the  thy- 
roid secretion  causes  an  increase  in  the  facility  with  which 
nervous  energy  is  discharged,  a  pathologic  reciprocal  inter- 
action is  established  between  the  brain  and  the  thyroid. 
The  effect  of  the  constantly  recurring  stimulus  of  the  noci- 
influence  is  heightened  by  summation.  This  reciprocal 
goading  may  continue  until  either  the  brain  or  the  thyroid 
is  destroyed.  If  the  original  noci-stimulus  is  withdrawn 
before  the  fear  of  the  disease  becomes  too  strong,  and  before 
too  much  injury  to  the  brain  and  the  thyroid  has  been  in- 
flicted, a  spontaneous  cure  may  result.  Recovery  may  be 
greatly  facilitated  by  complete  therapeutic  rest.  A  cure 
implies  the  return  of  the  brain-cells  to  their  normal  state, 
with  the  reestablishment  of  the  normal  self-control  and  the 
restoration  of  the  thyroid  to  its  normal  state,  when  the 
impulses  of  daily  life  will  once  more  have  possession  of  the 
final  common  path  and  the  noci-influence  will  be  dispossessed. 
The  discovery  of  the  real  cause  of  a  given  case  of  Graves' 
disease  is  frequently  difficult  because  it  may  be  of  a  painful 
personal  nature.  Of  extreme  interest  is  the  fact  that,  in 
the  acute  stage,  the  patient  may  be  unable  to  refer  to  the 
exciting  cause  without  exhibiting  an  exacerbation  of  the 
symptoms  of  the  disease.  I  presume  no  case  should  be  re- 
garded as  cured  until  reference  can  be  made  to  its  cause 
without  an  abnormal  reaction.  It  has  been  established  that 
in  Graves'  disease  injury  to  any  part  of  the  body,  even  under 
inhalation  anesthesia,  causes  an  exacerbation  of  the  disease. 
Fear  alone  may  cause  an  acute  exacerbation.     These  acute 


42 


THE    EMOTIONS 


exacerbations  are  frequently  designated  "hyperthyroidism" 
and  are  the  special  hazard  of  operation. 

In  applying  the  principle  of  anoci-association  in  operations 
on  patients  with  Graves'  disease  there  is  scarcely  a  change 
in  the  pulse,  in  the  respiration,  or  in  the  nervous  state  at 
the  close  of  the  operation.  I  know  no  remedy  which  can 
obviate  the  effect  of  the  inflowing  stimuli  from  the  wound 
after  the  cocain*  has  worn  off.f     It  is  necessary,  therefore. 


Bea-ts 

70 

80 

90 

100 

no 

120 

EtVier. 

NiO. 

Anoci. 

The  Pulse. 
Each  heavy  line  represents  the  average  5  p.  m.  pulse-rate  of  ten  patients  during  the  first  four 

days  after  operation. 

Fig.  17. — Comparative  Clinical  Results  of  Consecutive  Thyroidec- 
tomies Performed  under  Ether,  under  Nitrous-Oxid-Oxygen  Alone, 
AND  UNDER  COMPLETE  Anoci-association . 


not  to  venture  too  far  in  serious  cases.  Since  the  adoption 
of  this  new  method  (anoci-association)  my  operative  results 
have  been  so  vastly  improved  that  I  now  rarely  regard  any 
case  of  Graves'  disease  as  inoperable,  at  least  to  the  extent  of 
contraindicating  a  double  ligation  (Fig.  17). 

If  we  believe  that,  in  accordance  with  the  law  of  phylo- 
genetic  association,  a  continuous  stimulation  of  both  the 
brain  and  the  thyroid  gland,  accelerated  by  summation, 

*  See  footnote,  page  4. 

tin  later  papers  and  in  "Anoci-association"  (Crile  and  Lower)  methods 
of  combating  postoperative  hyperthyroidism  are  fully  discussed. 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    43 

plays  a  role  in  the  establishment  of  the  pathologic  interac- 
tion seen  in  Graves'  disease,  then  it  is  but  the  next  step  to 
assume  that  if  the  nerve  connection  between  the  brain  and 
the  thyroid  be  severed,  or  if  the  lobe  be  excised  and  the 
patient  reinforced  by  a  sojourn  in  a  sanatorium  or  in  some 
environment  free  from  former  noci-associations,  he  may  be 
restored  to  normal  health,  provided  that  the  brain-cells,  the 
heart,  or  other  essential  organs  have  not  suffered  irreparable 
damage.  There  are  still  many  missing  links  in  the  solution 
of  this  problem,  and  the  foregoing  hypotheses  are  not  offered 
as  final,  although  from  the  viewpoint  of  the  surgeon  many  of 
the  phenomena  of  this  disease  are  explicable. 

Sexual  Neurasthenia 
The  state  of  sexual  neurasthenia  is  in  many  respects 
analogous  to  that  of  Graves'  disease.  In  the  sexual  reflexes, 
summation  leads  to  a  hyperexcitability  by  psychic  and  me- 
chanical stimuli  of  a  specific  type  which  is  analogous  to  the 
hyperexcitabilit}'  in  Graves'  disease  under  trauma  and  fear; 
the  explanation  of  both  conditions  is  based  on  the  laws  of  the 
discharge  of  energy  by  phylogenetic  association  and  sum- 
mation. It  would  be  interesting  to  observe  the  effect  of 
interrupting  the  nerve  impulses  from  the  field  of  the  sexual 
receptors  by  injections  of  alcohol,  or  by  other  agencies,  so 
as  to  exclude  the  associational  stimuli  until  the  nervous 
mechanism  has  again  become  restored  to  its  normal  con- 
dition. 


44  THE   EMOTIONS 


Interpretation  of  Some  of  the  Phenomena  of  Certain  Diseases  of 

the  Abdomen  in  Accordance  with  the  Hypothesis  of  Phylo- 

genetic  Association 

The  law  of  phylogenetic  association  seems  to  explain 
many  of  the  phenomena  of  certain  lesions  in  the  abdominal 
cavity.  The  nociceptors  in  the  abdomen,  like  nociceptors 
elsewhere,  have  been  established  as  a  result  of  some  kind  of 
injury  to  which  during  vast  periods  of  time  this  region  has 
been  frequently  exposed.  On  this  premise,  we  should  at 
once  conclude  that  there  are  no  nociceptors  for  heat  within 
the  abdomen  because,  during  countless  years,  the  intra- 
abdominal region  never  came  into  contact  with  heat. 
That  this  inference  is  correct  is  shown  by  the  fact  that  the 
application  of  a  thermocautery  to  the  intestines  when  com- 
pleting a  colostomy  in  a  conscious  patient  is  absolutely 
painless.  One  would  conclude  also  that  there  are  no  touch 
receptors  in  the  abdominal  viscera,  and  therefore  no  sense 
of  touch  in  the  peritoneum.  Just  as  the  larynx,  the  ear, 
the  nose,  the  sole  of  the  foot,  and  the  skin  have  all  de- 
veloped the  specific  type  of  nociceptors  which  are  adapted 
for  their  specific  protective  purposes,  and  which,  when  ade- 
quately stimulated,  respond  in  a  specific  manner  in  accord- 
ance with  the  law  of  phylogenetic  association,  so  the  ab- 
dominal viscera  have  developed  equally  specific  nociceptors 
as  a  protection  against  specific  nocuous  influences.  The  prin- 
cipal harmful  influences  to  which  the  abdominal  viscera 
have  been  exposed  during  vast  periods  of  time  are  deep 
tearing  injuries  by  teeth  and  claws  in  the  innumerable 
struggles  of  our  progenitors  with  each  other  and  with  their 
enemies  (Fig.  9);   peritonitis  caused  by  perforations  of  the 


PHYLOGEXETIC    ASSOCIATIOX    AND    MEDICAL    PROBLEMS    45 

intestinal  tract  from  ulcers,  injuries,  appendicitis,  gall- 
stones, etc.;  and  overdistention  of  the  hollow  viscera  by 
various  forms  of  obstruction.  WTiatever  may  be  the  ex- 
planation, it  is  a  fact  that  the  type  of  trauma  which  results 
from  fighting  corresponds  closely  with  that  which  causes 
the  most  shock  in  the  experimental  laboratory.  Division 
of  the  intestines  with  a  sharp  knife  causes  no  pain,  but 
pulling  on  the  mesentery  elicits  pain.  Ligating  the  stump 
of  the  appendix  causes  sharp,  cramp-like  pains.  Sharp 
division  of  the  gall-bladder  causes  no  pain,  but  distention, 
which  is  the  gall-bladder's  most  common  pathologic  state, 
produces  pain.  Distention  of  the  intestine  causes  great 
pain,  but  sharp  cutting  or  burning  causes  none.  In  the 
abdominal  viscera,  as  in  the  superficial  parts,  nociceptors 
have  presumabh'  been  developed  by  specific  harmful  in- 
fluences and  each  nociceptor  is  open  to  stimulation  only  by 
a  stimulus  of  the  particular  type  that  produced  it. 

As  a  result  of  the  excitation  of  nociceptors,  with  which 
pain  is  associated,  the  routine  functions,  such  as  peristalsis, 
secretion,  and  absorption  are  dispossessed  from  the  control 
of  their  respective  nervous  mechanisms,  just  as  they  are 
inhibited  by  fear.  This  hypothesis  explains  the  loss  of 
weight,  the  lassitude,  the  indigestion,  the  constipation,  and 
the  many  alterations  in  the  functions  of  the  various  glands 
and  organs  of  the  digestive  system  in  chronic  appendicitis. 
It  readily  explains  also  the  extraordinary  improvement  in 
the  digestive  functions  and  the  general  health  which  foUows 
the  removal  of  an  appendix  which  is  so  slightly  altered 
physically  that  only  the  clinical  results  could  persuade  one 
that  this  slight  change  could  be  an  adequate  cause  for  such 
far-reaching   and   important    symptoms.     This   hypothesis 


46  THE    EMOTIONS 

explains  certain  gall-bladder  phenomena  likewise, — indi- 
gestion, loss  of  weight,  disturbed  functions,  etc., — and  it  may 
supply  the  explanation  of  the  disturbance  caused  by  an 
active  anal  fissure,  which  is  a  potent  noci-associator,  and  the 
consequent  disproportionate  relief  after  the  trivial  operation 
for  its  cure.  Noci-association  would  well  explain  also  the 
great  functional  disturbances  of  the  viscera  which  immedi- 
ately follow  abdominal  operations. 

Postoperative  and  traumatic  neuroses  are  at  once  ex- 
plained on  the  ground  of  noci-association,  the  resulting 
strain  from  which,  upon  the  brain-cells,  causes  in  them 
physical  lesions.  If  one  were  placed  against  a  wall  and 
were  looking  into  the  gun  muzzles  of  a  squad  of  soldiers, 
and  were  told  that  there  were  nine  chances  out  of  ten 
that  he  would  not  be  killed  outright  when  the  volley  was 
fired,  would  it  help  him  to  be  told  that  he  must  not  be 
afraid?  Such  an  experience  would  be  written  indelibly 
on  his  brain.  This  corresponds  closely  to  the  position 
in  which  some  surgical  patients  are  placed.  In  railway 
wrecks,  we  can  readily  understand  the  striking  difference 
between  the  after-effects  in  the  passengers  who  were  con- 
scious at  the  time  of  the  accident  and  those  who  were 
asleep  or  drunk.  In  the  latter  the  noci-perceptors  and 
receptors  were  not  aroused,  hence  their  immunity  to  the 
nervous  shock.  In  the  functional  disturbances  of  the  pelvic 
organs,  association  and  summation  may  play  a  large  role. 
On  this  hypothesis  many  cases  of  neurasthenia  may  well  be 
explained.  From  the  behavior  of  the  individual  as  a  whole 
we  may  well  conclude  that  summation  is  but  a  scientific 
expression  for  "nagging."  Many  other  pathologic  phenom- 
ena may  be  explained  in  a  similar  manner.     Thus  we  can 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL   PROBLEMS    47 

understand  the  variations  in  the  gastric  analyses  in  a  timid 
patient  alarmed  over  his  condition  and  afraid  of  the  hospital. 
He  is  integrated  by  fear,  and  as  fear  takes  precedence  over 
all  other  impulses,  no  organ  functionates  normally.  For 
the  same  reason,  one  sees  animals  in  captivity  pine  away 
under  the  dominance  of  fear.  The  exposure  of  a  sensitive 
brain  to  the  naked  possibility  of  death  from  a  surgical  opera- 
tion may  be  compared  to  uncovering  a  photographic  plate 
in  the  bright  sunlight  to  inspect  it  before  putting  it  in  the 
camera.  This  principle  explains,  too,  the  physical  influence 
of  the  physician  or  surgeon,  who,  by  his  personality ,  inspires, 
like  a  Kocher,  absolute  confidence  in  his  patient.  The  brain, 
through  its  power  of  phylogenetic  association,  controls  many 
processes  that  have  wholly  escaped  from  the  notice  of  the 
"practical  man."  It  is  in  accordance  with  the  law  of  asso- 
ciation that  a  flower,  a  word,  a  touch,  a  cool  breeze,  or  even 
the  thought  of  a  fishing  rod  or  of  a  gun,  is  helpful.  On  the 
contrary,  all  suggestions  of  despair  or  misfortune — a  cor- 
rugated brow,  the  gloomy  silence  of  despair,  or  a  doubtful 
word — are  equally  depressing.  In  like  manner,  one  could 
add  many  illustrations  of  the  symbolism  that  governs  our 
daily  lives.  Thus  we  see  that  through  the  laws  of  inherit- 
ance and  noci-association,  we  are  able  to  read  a  new  mean- 
ing into  the  clinical  phenomena  of  various  diseases. 

Observations  on  Patients  whose  Associational  Centers  are  DwIIed, 

and  on  Diseases  and  Injuries  of  Regions  not  Endowed 

with  Nociceptors 

Reversing  the  order  of  our  reasoning,  let  us  now  glance 
at  the  patient  who  is  unconscious  and  who,  therefore,  has 
lost  much  of  the  power  of  association.     His  mouth  is  usually 


48  THE    EMOTIONS 

dry,  the  digestive  processes  are  at  a  low  ebb,  the  aroma  of 
food  causes  no  secretion  of  saliva,  tickUng  the  nose  causes  no 
sneezing;  he  catches  no  cold.  The  laryngeal  reflex  is  lost 
and  food  may  be  quietly  inhaled;  the  entire  process  of 
metabolism  is  low.  The  contrast  between  a  man  whose 
associational  centers  are  keen  and  a  man  in  whom  these 
centers  are  dulled  or  lost  is  the  contrast  between  life  and 
death. 

In  accordance  with  the  law  of  adaptation  through  natural 
selection,  phylogeny,  and  association,  one  would  expect  no 
pain  in  abscess  of  the  brain,  in  abscess  of  the  liver,  in  pyle- 
phlebitis, in  infection  of  the  hepatic  vessels,  in  endocarditis. 
This  law  explains  why  there  are  no  nociceptors  for  cancer, 
while  there  are  active  nociceptors  for  the  acute  infections. 
It  is  because  nature  has  no  helpful  response  to  offer  against 
cancer,  while  in  certain  of  the  acute  pyogenic  infections  the 
nociceptors  force  the  beneficent  physiologic  rest. 

Could  we  dispossess  ourselves  of  the  shackles  of  psychol- 
ogy, forget  its  confusing  nomenclature,  and  view  the  human 
brain,  as  Sherrington  has  said,  ''as  the  organ  of,  and  for  the 
adaptation  of  nervous  reaction,"  many  clinical  phenomena 
would  appear  in  a  clearer  light. 

Natural    Selection    and    Chemical    Noci-association    in    the 

Infections 

Thus  far  we  have  considered  the  behavior  of  the  indi- 
vidual as  a  whole  in  his  response  to  a  certain  type  of  noci- 
influences.  We  have  been  voicing  our  argument  in  terms 
of  physical  escape  from  gross  physical  dangers,  or  of  grappling 
with  gross  nerve-muscular  enemies  of  the  same  or  of  other 
species.     To  explain  these  phenomena  we  have  invoked  the 


PHYLOGENETIC    ASSOCIATION   AND    MEDICAL    PROBLEMS    49 

aid  of  the  laws  of  natural  selection  and  phylogenetic  associa- 
tion. If  our  conclusions  be  correct,  then  it  should  follow 
that  in  the  same  laws  we  may  find  the  explanation  of  im- 
munity, which,  of  course,  means  a  defensive  response  to  our 
microscopic  enemies.  There  should  be  no  more  difficulty  in 
evolving  an  efficient  army  of  phagocytes  by  natural  selection, 
or  in  developing  specific  chemical  reactions  against  micro- 
scopic enemies,  than  there  was  in  evolving  the  various  noci- 
ceptors for  our  nerve-muscular  defense  against  our  gross 
enemies.  That  immunity  is  a  chemical  reaction  is  no  argu- 
ment against  the  application  of  the  law  of  natural  selection 
or  of  association.  What  essential  difference  is  there  between 
the  chemical  defense  of  the  skunk  against  its  nerve-muscular 
enemies  and  its  chemical  defense  (immunity)  against  its 
microscopic  enemies? 

The  administration  of  vaccines  becomes  the  adequate 
stimulus  which  awakens  phylogenetic  association  of  a 
chemical  nature  as  a  result  of  which  immune  bodies  are 
produced. 

In  discussing  this  subject  I  will  raise  only  the  question 
whether  or  not  the  specific  character  of  the  inaugural  symp- 
toms of  some  infectious  diseases  may  be  due  to  phylogenetic 
association.  These  inaugural  symptoms  are  measurably  a 
recapitulation  of  the  leading  phenomena  of  the  disease  in 
its  completed  clinical  picture.  Thus,  the  furious  initiative 
symptoms  of  pneumonia,  of  peritonitis,  or  erysipelas,  of  the 
exanthemata,  are  exaggerations  of  phenomena  which  are 
analogous  to  the  phenomena  accompanying  physical  injury 
and  fear  of  physical  violence.  Just  as  the  acute  phenomena 
of  fear,  or  those  which  accompany  the  adequate  stimulation 
of  nociceptors,  are  recapitulations  of  phylogenetic  struggles, 

4 


50  THE    EMOTIONS 

SO  may  the  inaugural  symptoms  of  an  infection  be  a  similar 
phylogenetic  recapitulation  of  the  course  of  the  disease.     A 
certain  amount  of  negative  evidence  is  supplied  by  a  com- 
parison of  the  response  to  a  dose  of  toxins  with  the  response 
to  a  dose  of  a  standard  drug.     No  drug  in  therapeutic  dosage 
except  the  iodin  compounds  causes  a  febrile  response;    no 
drug  causes  a  chill;    on  the  other  hand,  all  specific  toxins 
cause  febrile  responses  and  many  cause  chills.     If  a  species 
of  animal  had  been  poisoned  by  a  drug  during  vast  periods 
of  time,  and  if  natural  selection  had  successfully  established 
a  self-defensive  response,  then  the  administration  of  that 
drug  would  cause  a  noci-association  (chemical) ,  and  a  specific 
reaction  analogous  to  that  following  the  administration  of 
Coley's  toxins  might  be  expected.     Bacterial  noci-associa- 
tion probably  operates  through  the  same  law  as  that  through 
which  physical  noci-association  operates.     Natural  selection 
is  impartial,  however.     It  must  be  supposed  that  it  acts  im- 
partially upon  the  microscopic  invader  and  upon  the  host. 
On  this  ground  one  must  infer  that,  in  accordance  with  the 
same  law  of  natural  selection,  the  bacteria  of  acute  infec- 
tions have  met  by  natural  selection  each  advance  in  the 
struggle  of  the  host  for  immunity.     Hence  the  fast  and 
furious  struggle  between  m^an  and  his  microscopic  enemies 
merely  indicates  to  what  extent  natural  selection  has  de- 
veloped   the    attack    and    the    defense    respectively.     This 
struggle  is  analogous  to  the  quick  and  decisive  battles  of  the 
carnivora  when  fighting  among  themselves  or  when  con- 
tending against  their  ancient  enemies.     But  when  phylo- 
genetically  strange  animals  meet  each  other,  they  do  not 
understand  how  to  conduct  a  fight:  natural  selection  has  not 
had  the  opportunity  of  teaching  them.     The  acute  infec- 


PHYLOGEXETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    51 

tions  have  the  characteristics  of  being  ancient  enemies.  On 
this  hypothesis  one  can  understand  the  high  mortaUty  of 
measles  when  it  is  introduced  into  a  new  country.  By 
natural  selection,  measles  has  become  a  powerful  enemy  of 
the  human  race,  and  a  race  to  which  this  infection  is  newly 
introduced  has  not  had  the  advantage  of  building  up  a 
defense  against  it  by  the  law  of  natural  selection.  May  not 
the  phenomena  of  anaphylaxis  be  studied  on  associational 
lines?  Then,  too,  there  may  be  chemical  noci-associations 
with  enemies  now  extinct,  which,  like  the  ticklish  points, 
may  still  be  active  on  adequate  stimulation.  This  brief 
reference  to  the  possible  relation  of  the  phenomena  of  the 
acute  infections  to  the  laws  of  natural  selection  and  of  specific 
chemical  noci-association  has  been  made  as  a  suggestion. 
Since  the  doctrine  of  evolution  explains  all  or  nothing,  I 
have  included  many  phenomena  to  see  how  reasonable  or 
unreasonable  such  an  explanation  might  be. 

Recapitulation 
The  following  are  the  principal  points  presented:  In 
operations  under  inhalation  anesthesia  the  nerve  impulses 
from  the  trauma  reach  every  part  of  the  brain — the  cerebrum 
that  is  apparently  anesthetized  as  well  as  the  medulla  that 
is  known  to  remain  awake — the  proof  being  the  physiologic 
exhaustion  of  and  the  pathologic  change  in  the  nerve-cells. 
Under  ether  anesthesia  the  damage  to  the  nerve-cells  is  at 
least  four  times  greater  than  under  nitrous  oxid.  Inhalation 
anesthesia  is,  therefore,  but  a  veneer — a  mask  that  ''covers 
the  deep  suffering  of  the  patient."  The  cause  of  the  ex- 
haustion of  the  brain  is  the  discharge  of  nervous  energy  in  a 
futile  effort  to  energize  the  paralyzed  muscles  in  an  attempt 
to  escape  from  the  injury  just  as  if  no  anesthetic  had  been 


52  THE    EMOTIONS 

given.  The  exhaustion  is,  therefore,  of  the  same  nature  as 
that  from  overexertion,  but  if  the  nerve-paths  connecting 
the  field  of  operation  and  the  brain  be  blocked,  then  there  is 
no  discharge  of  nervous  energy  from  the  trauma,  and  con- 
sequently there  is  no  exhaustion,  however  severe  or  pro- 
longed the  operation  may  be. 

Fear  is  a  factor  in  many  injuries  and  operations.  The 
phenomena  of  fear  probably  are  exhibited  only  by  animals 
whose  natural  defense  is  nerve-muscular.  The  skunk,  the 
porcupine,  the  turtle,  have  little  or  no  fear.  Fear  is  born 
of  the  innumerable  injuries  which  have  been  inflicted  in  the 
course  of  evolution.  Fear,  like  trauma,  may  cause  physio- 
logic exhaustion  of  and  morphologic  changes  in  the  brain- 
cells.  The  representation  of  injury,  which  is  fear,  being 
elicited  by  phylogenetic  association,  may  be  prevented  by 
the  exclusion  of  the  noci-association  or  by  the  administration 
of  drugs  like  morphin  and  scopolamin,  which  so  impair  the 
associational  function  of  the  brain-cells  that  immunity  to 
fear  is  established.  Animals  whose  natural  defense  is  in 
muscular  exertion,  among  which  is  man,  may  have  their 
dischargeable  nervous  energy  exhausted  by  fear  alone,  or  by 
trauma  alone,  but  most  effectively  by  the  combination  of 
both.  What  is  the  mechanism  of  this  discharge  of  energy? 
It  is  the  adequate  stimulation  of  the  nociceptors  and  the 
physiologic  response  for  the  purpose  of  self-preservation. 
According  to  Sherrington,  the  nervous  system  responds  in 
action  as  a  whole  and  to  but  one  stimulus  at  a  time.  The 
integration  of  the  individual  as  a  whole  occurs  not  alone  in 
injury  and  fear,  but  also,  though  not  so  markedly,  as  a 
result  of  other  phylogenetic  associations,  such  as  those  of 
the  chase  and  procreation.  When  adequate  stimuli  are  re- 
peated with  such  rapidity  that  the  new  stimulus  is  received 


PHYLOGENETIC    ASSOCIATION    AND    MEDICAL    PROBLEMS    53 

before  the  effect  of  the  previous  one  has  worn  off,  a  higher 
maximum  effect  is  produced  than  is  possible  under  a  single 
stimulus,  however  powerful. 

Sexual  receptors  are  implanted  in  the  body  by  natural 
selection,  and  the  adequate  stimuli  excite  the  nerve-muscular 
reactions  of  conjugation  in  a  manner  analogous  to  the  action 
of  the  adequate  stimuli  of  the  nociceptors.  The  specific 
response  of  either  the  sexual  receptors  or  the  nociceptors  is 
at  the  expense  of  the  total  amount  of  nervous  energy  avail- 
able at  the  moment.  Likewise  in  daily  labor,  which,  in  the 
language  of  evolution,  is  the  chase,  nervous  energy  is  ex- 
pended. Under  the  dominance  of  fear  or  injury,  however, 
the  integration  is  most  nearly  absolute  and  probably  every 
expenditure  of  nervous  energy  which  is  not  required  for 
efforts  toward  self-preservation  is  arrested;  hence  fear  and 
injury  drain  the  cup  of  energy  to  the  dregs.  This  is  the 
potential  difference  between  fear  and  desire,  between  injury 
and  conjugation. 

What  is  the  practical  application  of  this?  In  operative 
surgery  there  is  introduced  a  new  principle,  which  removes 
from  surgery  much  of  the  immediate  risk  from  its  trauma 
by  establishing  anoci-association;  it  places  certain  of  the 
phenomena  of  fear  on  a  physical  basis;  it  explains  to  us  the 
physical  basis  for  the  impairment  of  the  entire  individual 
under  worry  or  misfortune;  it  makes  evident  the  physical 
results  of  the  daily  noci-associations  experienced  by  the  indi- 
vidual as  a  social  unit.  On  the  other  hand,  it  explains  the 
power  of  therapeutic  suggestion  and  of  other  influences 
which  serve  for  the  time  to  change  the  noci-integration ;  it 
shows  the  physical  basis  for  the  difference  between  hope 
and  despair;  it  explains  some  of  the  phenomena  of  Graves' 
disease,  of  sexual  neurasthenia,  possibly  of  hay-fever  and  of 


54  THE    EMOTIONS 

the  common  cold.  The  principle  is  probably  equally  ap- 
plicable to  the  acute  infections,  in  each  of  which  chemical 
noci-association  gives  rise  to  many  of  the  phenomena  of  the 
disease  and  it  explains  their  cure  by  natural  immunity  and 
by  vaccines.  This  hypothesis  should  teach  us  to  view  our 
patients  as  a  whole;  and  especially  should  it  teach  the 
surgeon  gentleness.  It  should  teach  us  that  there  is  some- 
thing more  in  surgery  than  mechanics,  and  something  more 
in  medicine  than  physical  diagnosis  and  drugs. 

Concltision 

The  brain-cells  have  existed  for  eons  and,  amid  the  vicissi- 
tudes of  change,  they  have  persisted  with  perhaps  less  alter- 
ation than  has  the  crust  of  the  earth.  Whether  in  man  or 
in  the  lower  animals,  they  are  related  to  and  obey  the  same 
general  biologic  laws,  thus  being  bound  to  the  entire  past  and 
performing  their  function  in  accordance  with  the  law  of 
phylogenetic  association. 

For  so  long  a  time  have  we  directed  our  attention  to  tu- 
mors, infections,  and  injuries  that  we  have  not  sufficiently 
considered  the  vital  force  itself.  We  have  viewed  each 
anatomic  and  pathologic  part  as  an  entity  and  man  as  an 
isolated  phenomenon  in  nature.  May  we  not  find  in  the  laws 
of  adaptation  under  natural  selection,  and  of  phylogenetic 
association,  the  master  key  that  will  disclose  to  us  the  ex- 
planation of  many  pathologic  phenomena  as  they  have 
already  explained  many  normal  phenomena? 

And  may  medicine  not  correlate  the  pathologic  phenomena 
of  the  sick  man  with  the  forces  of  evolution,  as  the  naturalists 
have  correlated  the  phenomena  of  the  sound  man,  and  thus 
may  not  disease,  as  well  as  health,  be  given  its  evolutionary 
setting? 


PHYLOGENETIC   ASSOCIATION   IN   RELATION   TO   THE 

EMOTIONS  * 

The  surgeon  is  familiar  with  the  manifestations  of  every 
variety  of  the  human  emotions  in  the  various  stations  of  hfe, 
from  infancy  to  senihty,  in  health  and  in  disease.  Not  only 
does  he  come  into  intimate  contact  with  the  emotions  dis- 
played by  the  victims  of  disease  and  of  accidents,  but  he 
also  observes  those  manifested  by  the  relatives  and  friends 
of  the  families  of  his  patients.  Moreover,  he  is  unhappily 
forced  to  notice  the  emotional  effect  upon  himself  when  he 
is  waging  an  unequal  battle  against  death — the  strain  and 
worry  at  a  crisis,  when  a  life  is  in  the  balance  and  a  single 
false  move  may  be  fatal,  is  an  experience  known  only  to  the 
operating  surgeon. 

For  the  data  for  this  paper,  therefore,  in  which  I  shall  for 
the  most  part  limit  my  discussion  to  the  strongest  of  all 
emotions — fear — I  have  drawn  largely  from  my  personal  ex- 
perience as  a  surgeon,  as  well  as  from  an  experimental  re- 
search in  which  I  have  had  the  valuable  assistance  of  my 
associates.  Dr.  H.  G.  Sloan,  Dr.  J.  B.  Austin,  and  Dr.  M.  L. 
Menten. 

I  believe  it  can  be  shown  that  it  is  possible  to  elicit  the 
emotion  of  fear  only  in  those  animals  that  utilize  a  motor 
mechanism  in  defense  against  danger  or  in  escape  from  it. 
For  example,  the  defense  of  the  skunk  is  a  diabolic  odor 
which  repels  its  enemies;   the  skunk  has  no  adequate  equip- 

*  Address  before  the  American  Philosophical  Society,  Philadelphia,  April 
22,  1911. 

55 


56  THE    EMOTIONS 

ment  for  defense  or  escape  by  muscular  exertion,  and  the 
skunk  therefore  shows  httle  or  no  fear.  Again,  certain 
species  of  snakes  are  protected  by  venom;  they  possess  no 
other  means  of  defense  nor  have  they  adequate  motor 
mechanisms  for  escape  and  they  show  no  fear.  Because  of 
their  strength  other  animals,  such  as  the  lion,  the  grizzly 
bear,  and  the  elephant,  show  but  little  fear  (Fig.  6).  Ani- 
mals which  have  an  armored  protection,  such  as  the  turtle, 
show  little  fear.  It  is,  therefore,  obvious  that  fear  is  not 
universal  and  that  the  emotion  of  fear  is  felt  only  by  those 
animals  whose  self-preservation  is  dependent  upon  an  un- 
certain adequacy  of  their  power  of  muscular  exertion  either 
for  defense  or  for  flight  (Fig.  7). 

What  are  the  principal  phenomena  of  fear?  They  are 
palpitation  of  the  heart,  acceleration  of  the  rate  and  altera- 
tion of  the  rhythm  of  the  respiration,  cold  sweat,  rise  in 
body  temperature,  tremor,  pallor,  erection  of  the  hair,  sus- 
pension of  the  principal  functions  of  digestion,  muscular 
relaxation,  and  staring  of  the  eyes  (Fig.  12).  The  functions 
of  the  brain  are  wholly  suspended  except  those  which  relate 
to  the  self -protective  response  against  the  feared  object. 
Neither  the  brain  nor  any  other  organ  of  the  body  can  re- 
spond to  any  other  lesser  stimulus  during  the  dominance  of 
fear. 

From  these  premises  it  would  appear  that  under  the  in- 
fluence of  fear,  most,  perhaps  all,  of  the  organs  of  the  body 
are  divided  sharply  into  two  classes:  First,  those  that  are 
stimulated,  and,  second,  those  that  are  inhibited.  Those 
that  are  stimulated  are  the  entire  muscular  system,  the 
vasomotor  and  locomotor  systems,  the  senses  of  perception, 
the  respiration,  the  mechanism  for  erecting  the  hair,  the 


PHYLOGENETIC    ASSOCIATION    AND    THE    EMOTIONS  57 

sweat-glands,  the  thyroid  gland,  the  adrenal  gland  (Cannon), 
and  the  special  senses.  On  the  other  hand,  all  the  digestive 
and  procreative  functions  are  inhibited.  What  is  the  sig- 
nificance of  this  stimulation  of  some  and  inhibition  of  other 
organs?  As  far  as  we  know,  the  stimulated  organs  increase 
the  efficiency  of  the  animal  for  fight  or  for  flight.  It  is 
through  skeletal  muscles  that  the  physical  attack  or  escape  is 
effected;  these  muscles  alone  energize  the  claws,  the  teeth, 
the  hoofs,  and  the  means  for  flight.  The  increased  action 
of  the  muscles  of  the  heart  and  the  blood-vessels  increases 
the  efficiency  of  the  circulation;  the  secretion  of  the  adrenal 
gland  causes  a  rise  in  the  blood-pressure ;  the  increased  action 
of  the  thyroid  gland  causes  an  increased  metabolic  activity; 
there  is  evidence  that  glycogen  is  actively  called  out,  this 
being  the  most  immediately  available  substance  for  the  pro- 
duction of  energy;  the  increased  activity  of  the  respiration 
is  needed  to  supply  the  greater  need  of  oxygen  and  the 
elimination  of  the  increased  amount  of  waste  products ;  the 
dilatation  of  the  nostrils  affords  a  freer  intake  of  air;  the 
increased  activity  of  the  sweat-glands  is  needed  to  regulate 
the  temperature  of  the  body  which  the  increased  metabolism 
causes  to  rise.  The  activity  of  all  the  organs  of  percep- 
tion— sight,  hearing,  smell — is  increased  in  order  that  the 
danger  may  be  more  accurately  perceived.  It  cannot  be  a 
mere  coincidence  that  the  organs  and  the  tissues  that  are 
stimulated  in  the  emotion  of  fear  are  precisely  those  that  are 
actually  utihzed  in  a  physical  struggle  for  self-preservation. 
Are  any  other  organs  stimulated  by  fear  except  those  that 
can  or  that  do  assist  in  making  a  defensive  struggle?  I  know 
of  none.  On  the  other  hand,  if  an  animal  could  dispense 
with  his  bulky  digestive  organs,  whose  functions  are  sus- 


58 


THE    EMOTIONS 


pended  by  fear,  if  he  could,  so  to  speak,  clear  his  decks  for 
battle,  it  would  be  to  his  advantage.  Although  the  marvel- 
ous versatility  of  natural  selection  apparently  could  devise 


Fig.  is. — Dying  Tiger  at  Bay. 
"Fear  is  a  phylogenetic  fight  or  flight."      (Photo  by  Underwood  and 

derwood,  N.  Y.) 


Un- 


no  means  of  affording  this  advantage,  it  nevertheless  shut 
off  the  nervous  current  and  saved  the  vital  force  which  is 
ordinarily  consumed  by  these  non-combatants  in  the  per- 
formance of  their  functions.     Whatever  may  be  the  origin 


PHYLOGENETIC    ASSOCIATION    AND    THE    EMOTIONS 


59 


of  fear,  its  phenomena  are  due  to  a  stimulation  of  all  the 
organs  and  tissues  that  add  to  the  efficiency  of  the  physical 
struggle  for  self-preservation  and  an  inhibition  of  the  func- 


FiG.  19. — The  Broad  Jump. 

Note  the  similarity  of  the  expression  to  the  facial  expression  of  fear  and  of 

anger  (Figs.  12  and  21).     (Wm.  J.  Brownlow,  drawn  from  photo.) 


tions  of  the  leading  organs  that  do  not  participate  in  that 
struggle — the  non-combatants,  so  to  speak. 

Fear  arose  from  injury,  and  is  one  of  the  oldest  and  surely 
the  strongest  emotion.  By  the  slow  process  of  vast  empiri- 
cism nature  has  evolved  the  wonderful  defensive  motor  me- 


60 


THE   EMOTIONS 


chanism  of  many  animals  and  of  man.  The  stimulation  of 
this  mechanism  leading  to  a  physical  struggle  is  action,  and 
the  stimulation  of  this  mechanism  without  action  is  emotion. 
We  may  say,  therefore,  that  fear  is  a  phylogenetic  fight  or 
flight  (Fig.  18).     On  this  hypothesis  all  the  organs  and  parts 


Fig.  20. — Finish  of  Relay  Race. 
Compare  the  facial  expression  of  the  runners  with  those  in  Figs.  12,  19,  22. 
These  pictures  illustrate  the  fact  that  the  same  mechanism  is  stimulated 
in  emotion  as  in  physical  action.     (Photo  by  Underwood  and  Underwood, 
N.  Y.) 


of  the  body  are  integrated,  connected,  or  correlated  for 
the  self-preservation  of  the  individual  by  the  activity  of  his 
motor  mechanism  (Figs.  12,  19,  and  20).  We  fear  not  in  our 
hearts  alone,  not  in  our  brains  alone,  not  in  our  viscera 
alone — fear  influences  every  organ  and  tissue;    each  organ 


PHYLOGENETIC    ASSOCIATION    AND    THE    EMOTIONS  61 

or  tissue  is  stimulated  or  inhibited  according  to  its  use  or 
hindrance  in  the  physical  struggle  for  existence.  By  thus 
concentrating  all  or  most  of  the  nerve  force  on  the  nerve- 
muscular  mechanism  for  defense,  a  greater  physical  power 
is  developed.  Hence  it  is  that  under  the  stimulus  of  fear 
animals  are  able  to  perform  preternatural  feats  of  strength. 
For  the  same  reason,  the  exhaustion  following  fear  will  be 
increased  as  the  powerful  stimulus  of  fear  drains  the  cup 
of  nervous  energy  even  though  no  visible  action  may  result. 
An  animal  under  the  stimulus  of  fear  may  be  Ukened  to  an 
automobile  with  the  clutch  thrown  out  but  whose  engine  is 
racing  at  full  speed.  The  gasoline  is  being  consumed,  the 
machinery  is  being  worn,  but  the  machine  as  a  whole  does 
not  move,  though  the  power  of  its  engine  may  cause  it  to 
tremble. 

When  this  conception  is  applied  to  the  human  beings  of 
today,  certain  mysterious  phenomena  are  at  once  elucidated. 
It  must  be  borne  in  mind  that  man  has  not  been  presented 
with  any  new  organs  to  meet  the  requirements  of  his  present 
state  of  civilization;  'ndeed,  not  only  does  he  possess  organs 
of  the  same  type  as  those  of  his  savage  fellows,  but  of  the  same 
type  also  as  those  possessed  by  the  lower  animals  even.  In 
fact,  man  has  reached  his  present  status  of  civilization  with 
the  primary  equipment  of  brut'sh  organs.  Perhaps  the 
most  striking  difference  between  man  and  animals  lies  in  the 
greater  control  which  man  has  gained  over  his  primitive 
instinctive  reactions.  As  compared  with  the  entire  duration 
of  organic  evolution,  man  came  down  from  his  arboreal 
abode  and  assumed  his  new  role  of  increased  domination 
over  the  physical  world  but  a  moment  ago.  And  now, 
though  sitting  at  his  desk  in  command  of  the  complicated 


62  THE    EMOTIONS 

machinery  of  civilization,  when  he  fears  a  business  catas- 
trophe his  fear  is  manifested  in  the  terms  of  his  ancestral 
physical  battle  in  the  struggle  for  existence.  He  cannot  fear 
intellectually,  he  cannot  fear  dispassionately,  he  fears  with 
all  his  organs,  and  the  same  organs  are  stimulated  and 
inhibited  as  if,  instead  of  it  being  a  battle  of  credit,  of 
position,  or  of  honor,  it  were  a  physical  battle  with  teeth  and 
claws.  Whether  the  cause  of  acute  fear  be  moral,  financial, 
social,  or  stage  fright,  the  heart  beats  wildly,  the  respirations 
are  accelerated,  perspiration  is  increased,  there  are  pallor, 
trembling,  indigestion,  dry  mouth,  etc.  The  phenomena 
are  those  which  accompany  physical  exertion  in  self-defense 
or  escape.  There  is  not  one  group  of  phenomena  for  the 
acute  fear  of  the  president  of  a  bank  in  a  financial  crash  and 
another  for  the  hitherto  trusted  official  who  suddenly  and 
unexpectedly  faces  the  imminent  probability  of  the  peni- 
tentiary ;  or  one  for  a  patient  who  unexpectedly  finds  he  has 
a  cancer  and  another  for  the  hunter  when  he  shoots  his  first 
big  game.  Nature  has  but  one  means  of  response  to  fear, 
and  whatever  its  cause  the  phenomena  are  always  the  same 
— always  physical. 

If  the  stimulus  of  fear  be  repeated  from  day  to  day, 
whether  in  the  case  of  a  mother  anxious  on  account  of  the 
illness  of  a  child;  a  business  man  struggling  against  failure; 
a  politician  under  contest  for  appointment;  a  broker  in  the 
daily  hazard  of  his  fortune;  litigants  in  legal  battle,  or  a 
jealous  lover  who  fears  a  rival;  the  countless  real  as  well  as 
the  baseless  fears  in  daily  life,  in  fact,  all  forms  of  fear,  as  it 
seems  to  me,  express  themselves  in  like  terms  of  ancestral 
physical  contests.  On  this  law,  fear  dominates  the  various 
organs  and  parts  of  the  body. 


PHYLOGENETIC    ASSOCIATION    AND    THE    EMOTIONS 


63 


Anger  and  fear  express  opposite  emotional  states.  Fear 
is  the  expression  of  a  strong  desire  to  escape  from  danger; 
anger,  of  a  strong  desire  to  attack  physically  and  to  vanquish 
opposition.  This  hypothesis  is  strongly  supported  by  the 
outward  expressions  of  fear  and  of  anger.     When  the  busi- 


FiG.  21. — AxGRY  Cat  Prepared  to  Fight. 


ness  man  is  conducting  a  struggle  for  existence  against  his 
rivals,  and  when  the  contest  is  at  its  height,  he  may  clench 
his  fists,  pound  the  table,  perhaps  show  his  teeth,  and  ex- 
hibit every  expression  of  physical  combat.  Fixing  the  jaw 
and  showing  the  teeth  in  anger  merely  emphasize  the 
remarkable  tenacity  of  phylogeny.     Although  the  develop- 


64  THE    EMOTIONS 

ment  of  the  wonderful  efficiency  of  the  hands  has  led  to  a 
modification  of  the  once  powerful  canines  of  our  progenitors, 
the  ancestral  use  of  the  teeth  for  attack  and  defense  is  at- 
tested in  the  display  of  anger.  In  all  stations  of  life  differ- 
ences of  opinion  may  lead  to  argument  and  argument  to 
physical  combats,  even  to  the  point  of  killing.  The  physical 
violence  of  the  savage  and  of  the  brute  still  lies  surprisingly 
near  the  surface  (Fig.  21). 

We  have  now  presented  some  of  the  reasons  based  largely 
on  gross  animal  behavior  why  fear  is  to  be  regarded  as  a 
response  to  phylogenetic  association  with  physical  danger. 
In  further  support  of  this  hypothesis,  I  shall  now  present 
some  clinical  and  experimental  evidence.  Although  there 
is  not  convincing  proof,  yet  there  is  evidence  that  the  effect 
of  the  stimulus  of  fear  upon  the  body  when  unaccompanied 
by  physical  activity  is  more  injurious  than  is  an  actual 
physical  contest  which  results  in  fatigue  without  gross 
physical  injury.  It  is  well  known  that  the  soldier  who,  while 
under  fire,  waits  in  vain  for  orders  to  charge,  suffers  more 
than  the  soldier  who  flings  himself  into  the  fray;  and  that  a 
wild  animal  endeavoring  to  avoid  capture  suffers  less  than 
one  cowering  in  captivity.  An  unexpressed  smouldering 
emotion  is  measurably  relieved  by  action.  It  is  probable 
that  the  various  energizing  substances  needed  in  physical 
combat,  such  as  the  secretions  of  the  thyroid,  the  adrenals 
(Cannon),  etc.,  may  cause  physical  injury  to  the  body  when 
they  are  not  consumed  by  action  (Fig.  22) . 

That  the  brain  is  definitely  influenced — damaged  even — by 
fear  has  been  proved  by  the  following  experiments :  Rabbits 
were  frightened  by  a  dog  but  were  neither  injured  nor  chased. 
After  various  periods  of  time  the  animals  were  killed  and 
their  brain-cells  compared  with  the  brain-cells  of  normal 


PHYLOGENETIC    ASSOCIATION    AND    THE    EMOTIONS 


65 


animals — wide-spread   changes   were   seen    (Fig.   13).     The 
principal  clinical  phenomena  expressed  by  the  rabbit  were 


Fig.  22. — The  damaging  effects  of  the  emotions  of  which  this  woman  has 
been  the  victim — whether  fear  or  anger,  or  both — are  plainly  evident  in  the 
pallid  face  and  the  typical  facies  of  intense  exhaustion.  (Photo  by  Brown 
Bros.,  N.  Y.) 

rapid  heart,   accelerated  respiration,   prostration,   tremors, 
and  a  rise  in  temperature.     The  dog  showed  similar  phenom- 


66  THE    EMOTIONS 

ena,  excepting  that,  instead  of  such  muscular  relaxation  as 
was  shown  by  the  rabbit,  it  exhibited  aggressive  muscular 
action.  Both  the  dog  and  the  rabbit  were  exhausted  but, 
although  the  dog  exerted  himself  actively  and  the  rabbit 
remained  physically  passive,  the  rabbit  was  much  more  ex- 
hausted. 

Further  observations  were  made  upon  the  brain  of  a  fox 
which  had  been  chased  for  two  hours  by  members  of  a  hunt 
club,  and  had  been  finally  overtaken  by  the  hounds  and 
killed.  Most  of  the  brain-cells  of  this  fox,  as  compared  with 
those  of  a  normal  fox,  showed  extensive  physical  changes 
(Fig.  4). 

The  next  line  of  evidence  is  offered  with  some  reservation, 
but  it  has  seemed  to  me  to  be  more  than  mere  idle  specula- 
tion. It  relates  to  the  phenomena  of  one  of  the  most  inter- 
esting diseases  in  the  entire  category  of  human  ailments — 
I  refer  to  exophthalmic  goiter,  or  Graves'  disease,  a  disease 
primarily  involving  the  emotions.  This  disease  is  frequently 
the  direct  sequence  of  severe  mental  shock  or  of  a  long  and 
intensely  worrying  strain.  The  following  case  is  typical: 
A  broker  was  in  his  usual  health  up  to  the  panic  of  1907; 
during  this  panic  his  fortune  and  that  of  others  were  for 
almost  a  year  in  jeopardy,  failure  finally  occurring.  During 
this  heavy  strain  he  became  increasingly  nervous  and  by 
imperceptible  degrees  there  developed  a  pulsating  enlarge- 
ment of  the  thyroid  gland,  an  increased  prominence  of  the 
eyes,  marked  increase  in  perspiration — profuse  sweating 
even — palpitation  of  the  heart,  increased  respiration  with 
frequent  sighing,  increase  in  blood-pressure;  there  were 
tremor  of  many  muscles,  rapid  loss  of  weight  and  strength, 
frequent  gastro-intestinal  disturbances,  loss  of  normal  con- 
trol of  his  emotions,  and  marked  impairment  of  his  mental 


PHYLOGENETIC    ASSOCIATION    AND    THE    EMOTIONS  67 

faculties.  He  was  as  completely  broken  in  health  as  in 
fortune.  These  phenomena  resembled  closely  those  of  fear 
and  followed  in  the  wake  of  a  strain  which  was  due  to  fear. 

In  young  women  exophthalmic  goiter  often  follows  in  the 
wake  of  a  disappointment  in  love;  in  women,  too,  it  fre- 
quently follows  the  illnesses  of  children  or  parents  during 
which  they  have  had  to  endure  the  double  strain  of  worry 
and  of  constant  care.  Since  such  strains  usually  fall  most 
heavily  upon  women,  they  are  the  most  frequent  victims  of 
this  disease.  Now,  whatever  the  exciting  cause  of  exoph- 
thalmic goiter,  whether  it  be  unusual  business  worry,  dis- 
appointment in  love,  a  tragedy,  or  the  illness  of  a  loved  one, 
the  symptoms  are  alike  and  closely  resemble  the  phenomena 
of  one  of  the  great  primitive  emotions.  How  could  dis- 
appointment in  love  play  a  role  in  the  causation  of  Graves' 
disease?  If  the  hypothesis  which  has  been  presented  as  an  ex- 
planation of  the  genesis  and  the  phenomena  of  fear  be  cor- 
rect, then  that  hypothesis  explains  also  the  emotion  of  love. 
If  fear  be  a  phylogenetic  physical  defense  or  escape  which 
does  not  result  in  muscular  action,  then  love  is  a  phylogenetic 
conjugation  without  physical  action.  The  quickened  pulse, 
the  leaping  heart,  the  accelerated  respiration,  the  sighing, 
the  glowing  eye,  the  crimson  cheek,  and  many  other  phenom- 
ena are  merely  phylogenetic  recapitulations  of  ancestral 
acts.  The  thyroid  gland  is  beheved  to  participate  in  such 
physical  activities.  Hence  it  may  well  follow  that  the  dis- 
appointed maiden  who  is  intensely  integrated  for  a  youth 
will,  at  every  thought  of  him,  be  subjected  by  phylogenetic 
association  to  a  specific  stimulation  analogous  to  that  which 
attended  the  ancestral  consummation.  Moreover,  a  happy 
marriage  has  many  times  been  followed  by  a  cure  of  the 


68  THE    EMOTIONS 

exophthalmic  goiter  which  appeared  in  the  wake  of  such  an 
experieace. 

The  victims  of  Graves'  disease  present  a  counterpart 
of  emotional  exhaustion.  That  the  emotions  in  Graves' 
disease  are  abnormally  acute  is  illustrated  by  my  personal 
observation  of  the  death  of  a  subject  of  this  disease  from  fear 
alone.  Whatever  the  exciting  cause  of  this  disease,  the  symp- 
toms are  the  same;  just  as  in  fear,  the  phenomena  are  the 
same  whatever  the  exciting  cause. 

Figures  12  and  16  show  the  resemblance  between  the  out- 
ward appearances  of  a  patient  with  Graves'  disease  and  of  a 
person  obsessed  by  fear.  Fear  and  Graves'  disease  have  the 
following  phenomena  in  common:  Increased  heart-beat, 
increased  respiration,  rising  temperature,  muscular  tremors, 
protruding  eyes,  loss  in  weight;  Cannon  has  found  an  in- 
creased amount  of  adrenalin  in  the  blood  in  fear  and  Frankel 
in  Graves'  disease;  increased  blood-pressure;  muscular 
weakness;  digestive  disturbances;  impaired  nervous  con- 
trol; hypersusceptibility  to  stimuli;  in  protracted  intense 
fear  the  brain-cells  show  marked  physical  changes,  and 
in  Graves'  disease  analogous  changes  are  seen  (Figs.  13  C 
and  15).  In  Graves'  disease  there  seems  to  be  a  composite 
picture  of  an  intense  expression  of  the  great  primitive  emo- 
tions. If  Graves'  disease  be  a  disease  of  the  great  primitive 
emotions,  or  rather  of  the  whole  motor  mechanism,  how  is  the 
constant  flow  of  stimulation  of  this  complicated  mechanism 
supplied?  It  would  seem  that  there  must  be  secreted  in 
excessive  amount  some  substance  that  activates  the  motor 
mechanism.  The  nervous  system  in  Graves'  disease  is 
hypersusceptible  to  stimuli  and  to  thyroid  extract.  It 
might  follow  that  even  a  normal  amount  of  thyroid  secretion 


PHYLOGENETIC    ASSOCIATION    AND    THE    EMOTIONS  69 

would  lead  to  excessive  stimulation  of  the  hypersusceptible 
motor  mechanism. 

This  condition  of  excessive  motor  activity  and  hyper- 
excitability  may  endure  for  years.  What  is  the  source  of 
this  pathologic  excitation?  The  following  facts  may  give  a 
clue.  In  suitable  cases  of  Graves'  disease,  if  the  thyroid 
secretion  is  sufficiently  diminished  by  a  removal  of  a  part  of 
the  gland  or  by  interrupting  the  nerve  and  the  blood  supply, 
the  phenomena  of  the  disease  are  diminished  immediately, 
and  in  favorable  cases  the  patient  is  restored  to  approxi- 
mately the  normal  condition.  The  heart  action  slows,  the 
respiratory  rate  falls,  the  restlessness  diminishes,  digestive 
disturbances  disappear,  tremors  decrease,  there  is  a  rapid 
increase  in  the  body  weight,  and  the  patient  gradually  re- 
sumes his  normal  state.  On  the  other  hand,  if  for  a  period 
of  time  extract  of  the  thyroid  gland  is  administered  to  a 
normal  individual  in  excessive  dosage,  there  will  develop 
nervousness,  palpitation  of  the  heart,  sweating,  loss  of 
weight,  slight  protrusion  of  the  eyes,  indigestion;  in  short, 
most  of  the  phenomena  of  Graves'  disease  and  of  the  strong 
emotions  will  be  produced  artificially  (Figs.  15  and  23). 
When  the  administration  of  the  thyroid  extract  is  discon- 
tinued, these  phenomena  may  disappear.  On  the  other  hand, 
when  there  is  too  little  or  no  thyroid  gland,  the  individual 
becomes  dull,  stupid,  and  emotionless,  though  he  may  be 
irritable ;  while  if  a  sufficient  amount  of  thyroid  extract  be 
given  to  such  a  patient  he  may  be  brought  back  to  his  normal 
condition. 

Hence  we  see  that  the  phenomena  of  the  emotions  may 
within  certain  limits  be  increased,  diminished,  or  abolished 


70  THE    EMOTIONS 

by  increasing,  diminishing,  or  totally  excluding  the  secre- 
tion of  the  thyroid  gland. 

Graves'  disease  may  be  increased  by  giving  thyroid  ex- 
tract and  by  fear.  It  may  be  diminished  by  removing  a 
part  of  the  gland,  or  by  interrupting  the  blood  and  nerve 
supply,  or  by  complete  rest.  In  addition,  at  some  stage  of 
Graves'  disease  there  is  an  increase  in  the  size  and  in  the 
number  of  the  secreting  cells.  These  facts  regarding  the 
normal  and  the  pathologic  supply  of  thyroid  secretion 
point  to  this  gland  as  one  of  the  sources  of  the  energizing 
substance  or  substances,  by  means  of  which  the  motor 
phenomena  of  animals  are  executed  and  their  emotions 
expressed. 

Anger  is  similar  to  fear  in  origin  and,  like  fear,  is  an  inte- 
gration and  stimulation  of  the  motor  mechanism  and  its 
accessories.  Animals  which  have  no  natural  weapons  for 
attack  experience  neither  fear  nor  anger,  while  the  animals 
which  have  weapons  for  attack  express  anger  principally 
by  energizing  the  muscles  used  in  attack.  Although,  as 
has  already  been  stated,  the  efficiency  of  the  hands  of  man 
has  largely  supplanted  the  use  of  the  teeth,  he  still  shows 
his  teeth  in  anger  and  so  gives  support  to  the  theory  that  this 
emotion  is  of  remote  ancestral  origin  and  proves  the  great 
persistence  of  phylogenetic  association.  On  this  conception 
we  can  understand  why  it  is  that  a  patient  consumed  by 
worry — which  to  me  signifies  interrupted  stimulation,  a 
state  of  alternation  between  hope  and  fear — suffers  so  many 
bodily  impairments  and  diseases  even.  This  hypothesis 
explains  the  slow  dying  of  animals  in  captivity.  It  explains 
the  grave  digestive  and  metabolic  disturbances  which  appear 
under  any  nerve  strain,  especially  under  the  strain  of  fear, 


PHYLOGENETIC    ASSOCIATION    AND    THE    EMOTIONS         71 


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PHYLOGENETIC    ASSOCIATION    AND    THE    EMOTIONS  73 

and  the  great  benefits  of  confidence  and  hope;  it  explains 
the  nervousness,  loss  of  weight,  indigestion — in  short,  the 
comprehensive  physical  changes  that  are  wrought  by  fear 
and  by  sexual  love  and  hate.  On  this  hypothesis  we  can 
understand  the  physical  influence  of  one  individual  over  the 
body  and  personality  of  another;  and  of  the  infinite  factors 
in  environment  that,  through  phylogenetic  association,  play 
a  role  in  the  functions  of  many  of  our  organs.  It  is  because 
under  the  uncompromising  law  of  survival  of  the  fittest  we 
were  evolved  as  motor  beings  that  we  do  not  possess  any 
organs  or  faculties  which  have  not  served  our  progenitors 
in  accomplishing  their  survival  in  the  relentless  struggle  of 
organic  forms  with  one  another.  We  are  now,  as  we  were 
then,  essentially  motor  beings,  and  the  only  way  in  which 
we  can  meet  the  dangers  in  our  environment  is  by  a  motor 
response.  Such  a  motor  response  implies  the  integration 
of  our  entire  being  for  action,  this  integration  involving  the 
activity  of  certain  glands,  such  as  the  adrenals  (Cannon), 
the  thyroid,  the  liver,  etc.,  which  throw  into  the  blood-stream 
substances  which  help  to  form  energy,  but  which,  if  no 
muscular  action  ensues,  are  harmful  elements  in  the  blood. 
While  this  motor  preparation  is  going  on,  the  entire  digestive 
tract  is  inhibited.  It  thus  becomes  clear  why  an  emotion 
is  more  harmful  than  action. 

Any  agency  that  can  sufficiently  inspire  faith,  —  dispel 
worry, — whether  that  agency  be  mystical,  human,  or  divine, 
will  at  once  stop  the  body-wide  stimulations  and  inhibitions 
which  cause  lesions  which  are  as  truly  physical  as  is  a  frac- 
ture. The  striking  benefits  of  good  luck,  success,  and  happi- 
ness ;  of  a  change  of  scene ;  of  hunting  and  fishing ;  of  opti- 
mistic and  helpful  friends,  are  at  once  explained  by  this 


74  THE    EMOTIONS 

hypothesis.  One  can  also  understand  the  difference  be- 
tween the  broken  body  and  spirits  of  an  animal  in  captivity 
and  its  buoyant  return  to  its  normal  condition  when  freed. 

But  time  will  not  permit  me  to  follow  this  tempting  lead, 
which  has  been  introduced  for  another  purpose — the  pro- 
posal of  a  remedy. 

Worries  either  are  or  are  not  groundless.  Of  those  that 
have  a  basis,  many  are  exaggerated.  It  has  occurred  to  me 
to  utilize  as  an  antidote  an  appeal  to  the  same  great  law  that 
originally  excited  the  instinctive  involuntary  reaction  known 
as  fear — the  law  of  self-preservation. 

I  have  found  that  if  an  intelligent  patient  who  is  suffering 
from  fear  can  be  made  to  see  so  plainly  as  to  become  firmly 
convinced  that  his  brain,  his  various  organs,  indeed  his  whole 
being,  could  be  physically  damaged  by  fear,  that  this  same 
instinct  of  self-preservation  will,  to  the  extent  of  his  con- 
viction, banish  fear.  It  is  hurling  a  threatened  active  mil- 
itant danger,  whose  injurious  influences  are  both  certain 
and  known,  against  an  uncertain,  perhaps  a  fancied,  one.  In 
other  words,  fear  itself  is  an  injury  which  when  recognized 
is  instinctively  avoided.  In  a  similar  manner  anger  may  be 
softened  or  banished  by  an  appeal  to  the  stronger  self- 
preserving  instinct  aroused  by  the  fear  of  physical  damage, 
such  as  the  physical  injury  of  brain-cells.  This  playing  of 
one  primitive  instinct  against  another  is  comparable  to  the 
effect  produced  upon  two  men  who  are  quarreling  when  a 
more  powerful  enemy  of  both  comes  threateningly  on  the 
scene. 

The  acute  fear  of  a  surgical  operation  may  be  banished 
by  the  use  of  certain  drugs  that  depress  the  associational 
power  of  the  brain  and  so  minimize  the  effect  of  the  prepara- 


PHYLOGENETIC    ASSOCIATION    AND    THE    EMOTIONS  75 

tions  that  usually  inspire  fear.  If,  in  addition,  the  entire 
field  of  operation  is  blocked  by  local  anesthesia  so  that  the 
associational  centers  are  not  awakened,  the  patient  will 
pass  through  the  operation  unscathed. 

The  phylogenetic  origin  of  fear  is  injury,  hence  injury  and 
fear  cause  the  same  phenomena.  In  their  quality  and  in 
their  phenomena  psychic  shock  and  traumatic  shock  are  the 
same.  The  perception  of  danger  by  the  special  senses  in  the 
sound  of  the  opening  gun  of  a  battle,  or  in  the  sight  of  a 
venomous  snake,  is  phylogenetically  the  same  and  causes 
the  same  effects  upon  the  entire  body  as  an  operation  under 
anesthesia  or  a  physical  combat  in  that  each  drives  the  motor 
mechanism.  The  use  of  local  anesthetics  in  the  operative 
field  prevents  nerve-currents  from  the  seat  of  injury  from 
reaching  the  brain  and  there  integrating  the  entire  body 
for  a  self -defensive  struggle.  The  result,  even  though  a 
part  of  the  brain  is  asleep  and  the  muscles  paralyzed,  is 
the  same  as  that  produced  by  the  interception  of  the  terri- 
fying sound  of  the  gun,  or  of  the  sight  of  the  dangerous 
reptile,  since  the  stimulation  of  the  motor  mechanism  is 
prevented. 

By  both  the  positive  and  the  negative  evidence  we  are 
forced  to  believe  that  the  emotions  are  primitive  instinctive 
reactions  which  represent  ancestral  acts ;  and  that  they  there- 
fore utilize  the  complicated  motor  mechanism  which  has  been 
developed  by  the  forces  of  evolution  as  that  best  adapted 
to  fit  the  individual  for  his  struggle  with  his  environment 
or  for  procreation. 

The  mechanism  by  which  the  motor  acts  are  performed 
and  the  mechanism  by  which  the  emotions  are  expressed 
are  one  and  the  same.     These  acts  in  their  infinite  complexity'' 


76  THE    EMOTIONS 

are  suggested  by  association — phylogenetic  association. 
When  our  progenitors  came  in  contact  with  any  exciting 
element  in  their  environment,  action  ensued  then  and  there. 
There  was  much  action — httle  restraint  or  emotion.  Civihzed 
man  is  really  in  auto-captivity.  He  is  subjected  to  innumer- 
able stimulations,  but  custom  and  convention  frequently 
prevent  physical  action.  When  these  stimulations  are  suffi- 
ciently strong  but  no  action  ensues,  the  reaction  constitutes 
an  emotion.  A  phylogenetic  fight  is  anger;  a  phylogenetic 
flight  is  fear;  a  phylogenetic  copulation  is  sexual  love,  and 
so  one  finds  in  this  conception  an  underlying  principle  which 
may  be  the  key  to  an  understanding  of  the  emotions  and  of 
certain  diseases. 


PAIN,  LAUGHTER,  AND  CRYING* 

PAIN 

Pain,  like  other  phenomena,  was  probably  evolved  for  a 
particular  purpose — surely  for  the  good  of  the  individual; 
like  fear  and  worry,  it  frequently  is  injurious.  What  then 
may  be  its  purpose? 

We  postulate  that  pain  is  one  of  the  phenomena  which 
result  from  a  stimulation  to  motor  action.  When  a  bare- 
foot boy  steps  on  a  sharp  stone  it  is  important  that  the  in- 
juring contact  be  released  as  quickly  as  possible;  and  there- 
fore physical  injury  pain  results  and  impels  the  required 
action.  Anemia  of  the  soft  parts  at  the  points  of  pressure 
results  from  prolonged  sitting  or  lying  in  one  position,  and 
as  a  result  pain  compels  a  muscular  action  that  shifts  the 
damaging  pressure — this  is  the  pain  of  anemia;  when  the 
rays  of  the  blazing  sun  shine  directly  upon  the  retina,  pain 
immediately  causes  a  protective  muscular  action — the  lid 
is  closed,  the  head  turns  away — this  is  light  pain;  when 
standing  too  close  to  a  blazing  fire  the  excessive  heat  causes 
a  pain  which  results  in  the  protective  muscular  action  of 
moving  away — this  is  heat  pain;  when  the  urinary  bladder 
is  acutely  overdistended  the  resultant  pain  induces  volun- 
tary as  well  as  involuntary  muscular  contraction — this  is 
evacuation  pain;  associated  with  defecation  is  a  character- 
istic warning  pain,  and  an  active  pain  which  induces  the  re- 
quired muscular  action — this,  like  the  pain  accompanying 

*  Address  delivered  before  the  John  Ashhurst,  Jr..  Surgical  Society  of  the 
University  of  Pennsylvania,  May  3,  1912. 


78  THE    EMOTIONS 

micturition,  is  an  evacuation  pain;  in  obstruction  of  the 
urinary  passages  and  of  the  large  and  the  small  intestine  the 
pain  is  exaggerated,  as  is  the  accompanying  muscular  con- 
traction— this  is  a  pathologic  evacuation  pain;  when  the 
fetus  reaches  full  term  and  labor  is  to  begin,  it  is  heralded 
by  pain  which  is  associated  with  rhythmic  contractions  of 
the  uterine  muscle;  later,  many  other  muscles  take  part 
in  the  birth  and  pain  is  associated  with  all  these  muscular 
contractions — these  are  labor  pains;  when  a  foreign  body, 
be  it  ever  so  small,  falls  upon  the  conjunctiva  or  cornea  there 
results  what  is  perhaps  the  acutest  pain  known,  and  quick 
and  active  muscular  action  follows — this  is  special  contact 
pain.  Special  pain  receptors  are  placed  in  certain  parts  of 
the  nose,  the  pharynx,  and  the  larynx,  the  stimulation  of 
which  causes  special  motor  acts,  such  as  sneezing,  hawking, 
coughing.  Curiously  vague  pains  are  associated  with  the 
protective  motor  act  of  vomiting  and  with  the  sexual  motor 
acts — these  may  be  termed  nausea  pains  and  pleasure  pains. 
We  now  see,  therefore,  that  against  the  injurious  physical 
contacts  of  environment,  against  heat  and  cold,  against 
damaging  sunlight,  against  local  anemia  when  resting  or 
sleeping,  the  body  is  protected  by  virtue  of  the  muscular 
action  which  results  from  pain.  Then,  too,  for  the  emptying 
of  the  pregnant  uterus,  for  the  evacuation  of  the  intestine 
and  of  the  urinary  bladder  as  normal  acts,  and  for  the  over- 
coming of  obstructions  in  these  tracts,  pain  compels  the 
required  muscular  actions.  For  passing  gall-stones  and 
urinary  calculi,  urgent  motor  stimuli  are  awakened  by  pain. 
For  each  of  these  diversified  pains  the  consequent  muscular 
action  is  specific  in  type,  distribution,  and  intensity.  This 
statement  is  so  commonplace  that  we  are  apt  to  miss  the 


PAIN,    LAUGHTER,    AND    CRYING  79 

significance  and  the  wonder  of  it.  It  is  probable  that  every 
nerve-ending  in  the  skin  and  every  type  of  stimulation  repre- 
sents a  separate  motor  pattern,  the  adequate  stimulation  of 
wliich  causes  always  the  same  response. 

Let  us  pass  on  to  the  discussion  of  another  and  perhaps 
even  more  interesting  type  of  pain,  that  associated  with 
infection.  Not  all  kinds  of  infection  are  painful;  and  in 
those  infections  that  may  be  associated  with  pain  there  is 
pain  onh^  when  certain  regions  of  the  body  are  involved. 
Among  the  infections  that  are  not  associated  with  pain  are 
scarlet  fever,  typhoid  fever,  measles,  malaria,  whooping- 
cough,  typhus  fever,  and  syphilis  in  its  early  stages.  The 
infections  that  are  usually,  though  not  always,  associated 
with  pain  are  the  pyogenic  infections.  The  pyogenic  in- 
fections and  the  exanthemata  constitute  the  great  majority 
of  infections  and  are  the  basis  of  the  discussion  which  follows. 

I  will  state  one  of  my  principal  conclusions  first,  i.  e., 
that  the  only  types  of  infection  that  are  associated  with  pain 
are  those  in  which  the  infection  may  be  spread  by  muscular 
action  or  those  in  which  the  fixation  of  parts  by  continued 
muscular  rigidity  is  an  advantage;  and,  further,  as  a  striking 
corollary,  that  the  type  of  infection  that  may  cause  muscular 
action  when  it  attacks  one  region  of  the  body  may  cause  no 
such  action  when  it  attacks  another  region. 

The  primary,  and  perhaps  the  most  striking,  difference 
between  the  painless  exanthemata  and  the  painful  pyogenic 
infections  is  that  in  the  case  of  the  exanthemata  the  pro- 
tective response  of  the  body  is  a  chemical  one, — the  formation 
of  antibodies  in  the  blood,  which  usually  produce  permanent 
immunity, — while  the  response  to  the  pyogenic  infections  is 
largely  phagocytic.     In  the  pj'ogenic   infections,   in   order 


80  THE    EMOTIONS 

to  protect  the  remainder  of  the  body,  which,  of  course,  enjoys 
no  immunity,  every  possible  barrier  against  the  spread  of  the 
infection  is  thrown  about  the  local  point  of  infection.  How 
are  these  barriers  formed?  First,  lymph  is  poured  out, 
then  the  part  is  fixed  by  the  continuous  contraction  of  the 
neighboring  muscles  and  by  the  inhibition  of  those  muscles 
that,  in  the  course  of  their  ordinary  function,  would  by  their 
contractions  spread  the  infection.  Wherever  there  is  pro- 
tective muscular  rigidity  there  is  also  pain.  On  the  other 
hand,  in  pyogenic  infections  in  the  substance  of  the  liver, 
in  the  substance  of  the  kidney,  within  the  brain,  in  the  retro- 
peritoneal space,  in  the  lobes  of  the  lung,  in  the  chambers  of 
the  heart  and  in  the  blood-vessels  of  the  chest  and  the  ab- 
domen, in  all  locations  in  which  muscular  contractions  can 
in  no  way  assist  in  localizing  the  disease,  pyogenic  infections 
produce  no  muscular  rigidity  and  no  pain.  Apparently, 
therefore,  only  those  infections  are  painful  which  are  as- 
sociated with  a  protective  muscular  contraction.  This  ex- 
plains why  tuberculosis  of  the  hip  is  painful,  while  tubercu- 
losis of  the  lung  is  painless. 

There  is  a  third  type  of  pain  which  modifies  muscular 
action  in  a  curious  way.  We  have  already  stated  that  local 
pain  serves  an  adaptive  purpose.  In  this  light  let  us  now 
consider  headache.  Headache  is  one  of  the  commonest 
initiatory  symptoms  of  the  various  infections,  especially 
of  those  infections  which  are  accompanied  by  no  local  pain 
and  by  no  local  muscular  action.  In  peritonitis,  cholecys- 
titis, pleurisy,  arthritis,  appendicitis,  salpingitis,  child-birth, 
in  obstructions  of  the  intestinal  and  the  genito-urinary  tract, 
in  short,  in  those  acute  processes  in  which  the  local  symptoms 
are  powerful  enough  to  govern  the  individual  as  a  whole, — 


PAIN,    LAUGHTER,    AND    CRYING  81 

to  make  him  lie  down  and  keep  quiet,  refuse  food  and  possi- 
bly reject  what  is  already  in  the  stomach, — in  all  these  con- 
ditions there  is  rarely  a  headache,  but  in  the  diseases  in 
which  local  pain  is  absent,  such  as  the  exanthemata,  typhoid 
fever,  and  auto-intoxication,  which  have  no  dominating 
local  disturbances  to  act  as  policemen  to  put  the  individual 
to  bed  and  to  make  him  refuse  food  that  he  may  be  in  the 
most  favorable  position  to  combat  the  oncoming  disease, 
in  such  cases  in  which  these  masterful  and  beneficent  local 
influences  are  absent  we  postulate  that  headache  has  been 
evolved  to  perform  this  important  service. 

On  the  hypothesis  that  it  is  good  for  the  individual  who 
is  acutely  stricken  by  a  disease  or  who  is  poisoned  by  auto- 
intoxication to  rest  and  fast,  and  that  the  muscular  system 
obeys  the  imperial  command  of  pain,  and  in  view  of  the 
fact  that  the  brain  is  not  only  in  constant  touch  with  the 
conditions  of  every  part  of  the  body  but  that  it  is  also  the 
controlling  organ  of  the  body,  one  would  expect  that  in  these 
diseases  the  major  pain  whose  purpose  it  is  to  govern  general 
muscular  action  would  be  located  in  the  head  and  there  we 
find  it.  How  curious  and  yet  how  intelligible  is  the  fact 
that,  though  a  headache  may  be  induced  by  even  a  slight 
auto-intoxication,  an  abscess  may  exist  within  the  brain 
without  causing  pain.  When  an  obliterative  endarteritis  is 
threatening  a  leg  with  anemic  gangrene,  or  when  one  lies 
too  long  in  the  same  position  on  a  hard  bed,  there  is  threaten- 
ing injury  from  local  anemia,  and  as  a  result  there  is  acute 
pain,  but  when  the  obliterative  endarteritis  threatens  anemia 
of  the  brain,  or  when  an  embolism  or  thrombosis  has  pro- 
duced anemia  of  the  brain,  there  may  be  no  accompanying 
pain.  The  probable  explanation  of  the  pain  which  results 
6 


82  THE    EMOTIONS 

in  the  first  instance  and  the  lack  of  pain  in  the  second  is  that 
in  the  former  muscular  action  constitutes  a  self-protective 
response,  but  in  the  other  it  does  not.  Diseases  and  in- 
juries of  the  brain  are  notoriously  difficult  to  diagnosticate. 
This  may  well  be  because  it  has  always  been  so  well  pro- 
tected by  the  skull  that  there  have  been  evolved  within  it 
few  tell-tale  self-protective  responses,  so  that  in  the  presence 
of  inj  ury  and  disease  within  itself  the  brain  remains  remark- 
ably silent.  It  should  occasion  no  surprise  that  there  are  in 
the  brain  no  receptors,  the  mechanical  stimulation  of  which 
can  cause  pain,  because  its  bony  covering  has  always  pre- 
vented the  adaptive  implantation  within  it  of  contact  pain 
receptors.  Dr.  Frazier  tells  me  that  in  the  course  of  his 
operations  on  the  brains  of  unanesthetized  patients  he  is 
able  to  explore  the  entire  brain  freely  and  without  pain. 
From  my  own  experience  I  am  able  to  confirm  Dr.  Frazier' s 
observation.  In  addition,  the  two-stage  operation  for  the 
excision  of  the  Gasserian  ganglion  provides  an  observation 
of  extraordinary  interest.  If  at  the  first  seance  the  ganglion 
is  exposed,  but  is  not  disturbed  except  by  the  iodoform  gauze 
packing,  then  on  the  following  day  the  gauze  may  be  re- 
m.oved,  the  ganglion  picked  up,  and  its  branches  and  root 
excised  without  anesthesia  and  without  pain.  The  same 
statement  and  explanation  may  be  made  regarding  the  dis- 
tribution of  pain  receptors  for  physical  contact  within  the 
parenchyma  of  the  liver,  the  gall-bladder,  the  abdominal 
viscera,  the  spleen,  the  heart,  the  lungs,  the  retroperitoneal 
tissue,  the  deep  tissue  of  the  back,  the  vertebrae,  and  in 
certain  portions  of  the  spinal  cord.  Just  what  is  the  dis- 
tribution of  the  receptors  for  heat  and  for  cold  I  am  unable 
to  state,  but  this  much  we  do  know,  that  without  anesthesia 


PAIN,    LAUGHTER,    AND    CRYING  83 

the  intestines  may  be  cauterized  freely  without  the  least 
pain  resulting,  and  in  animals  the  cauterization  of  the  brain 
causes  no  demonstrable  change  in  the  circulatory  or  respira- 
tory reactions.  It  is  probable  therefore  that  the  distribution 
of  the  pain  receptors  for  physical  contact  and  for  heat  are 
limited  to  those  parts  of  the  body  that  have  been  exposed 
to  injurious  contacts  with  environment. 

Of  special  significance  is  the  pain  which  is  due  to  cold, 
which  increases  muscular  tone  and  produces  shivering. 
The  general  increase  in  muscular  tone  produces  an  interest- 
ing postural  phenomenon :  the  limbs  are  flexed  and  the  body 
bent  forward,  a  position  which  probably  is  due  to  the  fact 
that  the  flexors  are  stronger  than  the  extensors.  As  mus- 
cular action  is  always  accompanied  by  heat  production,  the 
purpose  of  the  muscular  contraction  and  the  shivering  is 
quite  certainly  caused  by  cold  to  assist  in  the  maintenance 
of  the  normal  body  temperature. 

We  have  now  discussed  many  of  the  causes  of  pain  and  in 
each  instance  we  have  found  an  associated  muscular  action 
which  apparently  serves  some  adaptive  purpose  (Figs.  24 
and  25).  If  we  assume  that  pain  exists  for  the  purpose  of 
stimulating  muscular  reactions,  we  may  well  inquire  what 
part  of  the  nervous  arc  is  the  site  of  the  sensation  of  pain — 
the  nerve-endings,  the  trunk,  or  the  brain?  Does  pain  re- 
sult from  physical  contact  with  the  nerve-endings,  with  the 
physical  act  of  transmitting  an  impression  along  the  nerve 
trunk,  or  with  the  process  within  the  brain-cells  by  which 
energy  is  released  to  cause  a  motor  act? 

It  seems  most  probable  that  the  site  of  the  pain  is  in  the 
brain-cells.  If  this  be  so,  then  what  is  the  physical  process 
by  which  the  phenomena  of  pain  are  produced?     The  one 


84 


THE    EMOTIONS 


Fig.  24. — The  Laocoon. 

The  muscular  activation  and  facies  of  the  father  most  strikingly  illustrate  the 

physical  expression  of  pain. 


PAIN,    LAUGHTER,    AND    CRYING 


85 


hypothesis  that  can  be  tested  experimentally  is  that  pain  is 
a  phenomenon  resulting  from  the  rapid  discharge  of  energy 
in  the  brain-cells.  If  this  be  true,  then  if  every  pain  receptor 
of  the  body  were  equally  stimulated  in  such  a  manner  that 


Fig.  25. — Fear  and  Agony. 

"Amid  this  dread  exuberance  of   woe  ran  naked  spirits  wing'd  with  horrid 

fear."— Dante's  "Inferno,"  Canto  XXIV,  Hnes  89,  90. 


all  the  stimuli  reached  the  brain-cells  simultaneously,  the 
cells  would  find  themselves  in  equilibrium  and  no  motor  act 
would  be  performed.  But  if  all  the  pain  receptors  of  the 
body  but  one  were  equally  stimulated,  and  this  one  stimu- 


»b  THE    EMOTIONS 

lated  harder  than  the  rest,  then  the  latter  would  gain  pos- 
session of  the  final  common  path,  the  sensation  of  pain 
would  be  felt,  and  a  muscular  contraction  would  result. 

It  is  well  known  that  when  a  greater  pain  is  thrown  into 
competition  with  a  lesser  one,  the  lesser  is  completely  sub- 
merged. In  this  manner  the  school-boy  initiates  the  novice 
into  the  mystery  of  the  painless  plucking  of  hair.  The 
simultaneous,  but  severe  application  of  the  boot  to  the 
blindfolded  victim  takes  complete  and  exclusive  possession 
of  the  final  common  path  and  the  hair  is  painlessly  plucked 
through  the  triumph  of  the  boot  stimulus  over  the  hair 
stimulus  in  the  struggle  for  the  possession  of  the  final  com- 
mon path. 

Another  argument  in  favor  of  this  hypothesis  that  pain  is 
an  accompaniment  of  the  release  of  energy  in  the  brain- 
cells  is  found  in  the  fact  that  painless  stimuh  received  through 
the  special  senses  may  completely  submerge  the  painful 
stimuli  of  physical  injury;  for  although  the  stimuli  to  motor 
action,  which  are  received  through  the  senses  of  sight,  hear- 
ing, and  smell,  cause  even  more  powerful  motor  action  than 
those  caused  by  physical  contact  stimuli,  yet  they  are  not 
accompanied  by  pain.  Examples  of  this  triumph  of  stimula- 
tion of  the  special  senses  over  contact  stimulation  are  fre- 
quently seen  in  persons  obsessed  by  anger  or  fear,  and  to  a 
less  degree  in  those  obsessed  by  sexual  emotion.  In  the  fury 
of  battle  the  soldier  may  not  perceive  his  wound  until  the 
emotional  excitation  is  wearing  away,  when  the  sensation  of 
warm  blood  on  the  skin  may  first  attract  his  attention.  Re- 
ligious fanatics  are  said  to  feel  no  pain  when  they  subject 
themselves  to  self-injury.  Now,  since  both  psychic  and 
mechanical  stimuli  cause  motor  action  by  the  excitation  of 


PAIN,    LAUGHTER,    AND    CRYING  87 

precisely  the  same  mechanism  in  the  brain,  and  since  the 
more  rapid  release  of  energy  from  psychic  stimuli  submerges 
the  physical  stimuli  and  prevents  pain,  it  would  seem  that 
pain  must  be  a  phenomenon  which  is  associated  with  the 
process  of  releasing  energy  by  the  brain-cells.  Were  physical 
injury  inflicted  in  a  quiescent  state  equal  to  that  inflicted  in 
the  emotional  state,  great  pain  and  intense  muscular  action 
would  be  experienced.  Now  the  emotions  are  as  purely 
motor  excitants  as  is  pain.  The  dynamic  result  is  the  same, 
the  principal  difference  being  the  greater  suddenness  and 
the  absolute  specificity  of  the  pain  stimuli  as  compared  with 
the  more  complex  and  less  peremptory  stimuli  of  the  emo- 
tions. A  further  evidence  that  pain  is  a  product  of  the 
release  of  brain-cell  energy  is  the  probability  that  if  one  could 
pierce  the  skin  at  many  points  on  a  limb  in  such  a  manner 
that  antagonistic  points  only  were  equally  and  simultane- 
ously stimulated,  then  an  equilibrium  in  the  governing  brain- 
cells  would  be  established  and  neither  pain  nor  motion  would 
follow.  An  absolute  test  of  this  assumption  cannot  be  made 
but  it  is  supported  by  the  obtainable  evidence. 

We  will  now  turn  to  a  new  viewpoint,  a  practical  as  well 
as  a  fascinating  one,  which  can  best  be  illustrated  by  two 
case  h'stories:  A  man,  seventy-eight  years  old,  whose  chief 
complaint  was  obstinate  constipation,  was' admitted  to  the 
medical  ward  of  the  Lakeside  Hospital  several  years  ago. 
The  abdomen  was  but  slightly  distended;  there  was  no 
fever,  no  increased  leukocytosis,  no  muscular  rigidity,  and 
but  slight  general  tenderness.  He  claimed  to  have  lost  in 
weight  and  strength  during  the  several  months  previous  to 
his  admission.  A  tentative  diagnosis  of  malignant  tumor 
of  the  large  intestine  was  made,  but  free  movements  were 


88  THE    EMOTIONS 

secured  rather  easily,  and  we  abandoned  the  idea  of  an  ex- 
ploratory operation.  The  patient  gradually  failed  and  died 
without  a  definite  diagnosis  having  been  made  by  either  the 
medical  or  the  surgical  service.  At  autopsy  there  was  found 
a  wide-spread  peritonitis  arising  from  a  perforated  appendix. 

A  child,  several  years  old,  was  taken  ill  with  some  indefinite 
disease.  A  number  of  the  ablest  medical  and  surgical  con- 
sultants of  a  leading  medical  center  thoroughly  and  repeat- 
edly investigated  the  case.  Although  they  could  make  no 
definite  diagnosis  they  all  agreed  that  the  trouble  surely 
could  not  be  appendicitis  because  there  was  neither  muscular 
rigidity  nor  tenderness.  The  autopsy  showed  a  gangrenous 
appendix  and  general  peritonitis. 

How  can  these  apparently  anomalous  cases  be  explained? 
These  two  cases  are  illustrations  of  the  same  principle  that 
underlies  the  freedom  from  pain  which  results  from  the  use 
of  narcotics  and  anesthetics,  the  same  principle  that  explains 
the  fact  that  cholecystitis  may  occur  in  the  aged  without  any 
other  local  symptoms  than  the  presence  of  a  mass  and  per- 
haps very  slight  tenderness;  and  that  accounts  in  general 
for  the  lack  of  well-expressed  disease  phenomena  in  senility 
and  in  infancy.  The  reason  why  the  aged,  the  very  young, 
and  the  subjects  of  general  paresis  show  but  few  symptoms 
of  disease  is  that  in  senility  the  brain  is  deteriorated,  while 
in  infancy  the  brain  is  so  undeveloped  that  the  mechanism  of 
association  is  inactive,  hence  pain  and  tenderness,  which  are 
among  the  oldest  of  the  associations,  are  wanting.  Senility 
and  infancy  are  by  nature  normally  narcotized.  The  senile 
are  passing  through  the  twilight  into  the  night ;  while  infants 
are  traversing  through  the  dawn  into  the  day.  Hence  it  is 
that  the  diagnosis  of  injury  and  disease  in  the  extremes  of 


PAIN,    LAUGHTER,    AND    CRYING  89 

life  is  beset  by  especial  difficulties,  since  the  entire  body  is  as 
silent  as  are  the  brain,  the  pericardium,  the  mediastinum,  and 
other  symptomless  areas. 

For  the  same  reason,  when  a  patient  who  is  seriously  ill 
with  a  painful  disease  turns  upon  the  physician  a  glowing 
eye  and  an  eager  face,  and  remarks  how  comfortable  he 
feels,  then  the  end  is  near.  This  is  a  brilliant  and  fateful 
clinical  mirage. 

When  one  reflects  on  the  vast  amount  of  evidence  as  to  the 
origin  and  the  purpose  of  pain,  he  is  forced  to  conclude  that 
pain  is  a  phenomenon  of  motor  stimulation,  and  that  its 
principal  role  is  the  protection  of  the  individual  against  the 
gross  and  the  microscopic  enemies  in  his  environment.  The 
benefits  of  pain  are  especially  manifested  in  the  urgent 
muscular  actions  by  means  of  which  the  body  moves  away 
from  physical  injury;  obstructions  of  the  hollow  viscera  are 
overcome;  rest  is  compelled  in  the  acute  infections — the 
infected  points  are  held  rigidly  quiet,  the  muscles  of  the  ab- 
domen are  fixed,  and  harmful  peristalsis  is  arrested  in 
peritonitis;  while  there  is  absolutely  no  pain  in  the  diseases 
or  injuries  which  affect  those  regions  of  the  body  in  which 
in  the  course  of  evolution  no  pain  receptors  were  placed,  or 
in  those  diseases  in  which  muscular  inhibition  or  contraction 
is  of  no  help.  In  a  biologic  sense  pain  is  closely  associated 
with  the  emotional  stimuli,  for  both  pain  and  the  emotions 
incite  motor  activity  for  the  good  of  the  individual. 

The  frequent  occurrence  of  post-operative  and  post- 
traumatic pain  is  accounted  for  by  the  fact  that  the  opera- 
tion or  the  injury  has  lowered  the  threshold  of  the  brain- 
cells  to  trauma;  the  brain  and  not  the  local  sensitive  field 
is  the  site  of  the  pain.     I  have  found  that,  by  blocking 


90  THE    EMOTIONS 

the  field  of  operation  with  local  anesthesia,  post-operative 
pain  is  diminished;  that  is,  since  the  local  anesthesia  pre- 
vents the  strong  stimuli  of  the  trauma  from  reaching  the 
brain,  its  threshold  is  not  lowered.  There  is  a  close  re- 
semblance between  the  phenomena  of  pain  habit,  of  educa- 
tion, of  physical  training,  of  love  and  of  hate.  In  educa- 
tion, in  pain  habit,  in  all  emotional  relations,  a  low  brain- 
cell  threshold  is  established  which  facilitates  the  reception 
of  specific  stimuli;  all  these  processes  are  motor  acts,  or 
are  symbolic  of  motor  acts,  and  we  may  be  trained  to  per- 
ceive misfortune  and  pain  as  readily  as  we  are  trained  to 
perceive  mathematical  formulae  or  moral  precepts.  In  each 
and  every  case,  readiness  of  perception  depends,  as  it  seems 
to  me,  upon  a  modified  state  of  the  brain-cells,  their  thres- 
hold especially,  the  final  degree  of  perception  possible  in  any 
individual  being  perhaps  based  on  the  type  of  potential 
molecules  of  which  the  brain  is  built.  We  must  believe  also 
that  every  impression  is  permanent,  as  only  thus  could  an 
individual  animal  or  a  man  be  fitted  by  his  own  experience 
for  life's  battles. 

LAUGHTER  AND  CRYING 

What  is  laughter?  What  is  its  probable  origin,  its  dis- 
tribution, and  its  purpose? 

Laughter  is  an  involuntary  rhythmic  contraction  of  certain 
respiratory  muscles,  usually  accompanied  by  certain  vocal 
sounds.  It  is  a  motor  act  of  the  respiratory  apparatus 
primarily,  although  if  intense  it  may  involve  not  only  the 
extraordinary  muscles  of  respiration,  but  most  of  the  muscles 
of  the  body.  There  are  many  degrees  of  laughter,  from  the 
mere  brightening  of  the  eyes,  a  fleeting  smile,  tittering  and 


PAIN,    LAUGHTER,    AND    CRYING  91 

giggling,  to  hysteric  and  convulsive  laughter.  Under  cer- 
tain circumstances,  laughter  may  be  so  intense  and  so  long 
continued  that  it  leads  to  considerable  exhaustion. 

The  formation  of  tears  is  sometimes  associated  with 
laughter.  When  integrated  with  laughter,  the  nervous 
system  can  perform  no  other  function.  Crying  is  closely 
associated  with  laughter,  and  in  children  especially  laughter 
and  crying  are  readily  interchanged. 

We  postulate  that  laughter  and  weeping  serve  a  useful 
purpose.  According  to  Darwin,  only  man  and  monkeys 
laugh  (Fig.  26) ;  other  animals  exhibit  certain  types  of  facial 
expression  accompanying  various  emotions,  but  laughter  in 
the  sense  in  which  that  word  is  commonly  used  is  probably 
an  attribute  of  the  primates  only,  although  it  is  probable 
that  many  animals  find  substitutes  for  laughter. 

The  proneness  of  man  to  laughter  is  modified  by  age,  sex, 
training,  mental  state,  health,  and  by  many  other  factors. 
Healthy,  happy  children  are  especially  prone  to  laughter, 
while  disease,  strong  emotions,  fatigue,  and  age  diminish 
laughter.  Women  laugh  more  than  do  men.  The  healthy, 
happy  maturing  young  woman  perhaps  laughs  most,  especi- 
ally when  she  is  slightly  embarrassed. 

What  causes  laughter?  Good  news,  high  spirits,  tickling, 
hearing  and  seeing  others  laugh;  droll  stories;  flashes  of 
wit;  passages  of  humor;  averted  injury;  threatened  breach 
of  the  conventions;  and  numerous  other  causes  might  be 
added.  It  is  obvious  that  laughter  may  be  produced  by 
diverse  influences,  many  of  which  are  so  unlike  each  other 
that  it  would  at  first  sight  seem  improbable  that  a  single 
general  principle  underlies  all.  Before  presenting  a  hypoth- 
esis which  harmonizes  most  of  the  facts,  and  which  may 


92 


THE    EMOTIONS 


offer  an  explanation  of  the  origin  and  purpose  of  laughter, 
let  us  return  for  a  moment  to  some  previous  considerations — 
that  man  is  essentially  a  motor  being;  that  all  his  re- 
sponses to  the  physical  forces  of  his  environment  are  motor; 


Fig.  26. — Laughing  Chimpanzee. 

"Mike,"  the  clever  chimpanzee  in  the  London  Zoo,  evidently  enjoys  a  joke  as 

well  as  any  one  else.     (Photo  by  Underwood  and  Underwood,  N.  Y.) 


that  thoughts  and  words  even  are  symbolic  of  motor  acts; 
that  in  the  emotions  of  fear,  of  anger,  and  of  sexual  love  the 
whole  body  is  integrated  for  acts  which  are  not  performed. 
These  integrations  stimulate  the  brain-cells,  the  ductless 
glands,  and  other  parts,  and  the  energizing  secretions,  among 


PAIN,    LAUGHTER,    AND    CRYING  93 

which  are  epinephrin,  thyroid  and  hypophyseal  secretions, 
are  thrown  into  the  blood-stream,  while  that  most  available 
fuel,  glycogen,  is  also  mobilized  in  the  blood.  This  body- 
wide  preparation  for  action  may  be  designated  kinetic  reac- 
tion. The  fact  that  emotion  is  more  injurious  to  the  body 
than  is  muscular  action  is  well  known,  the  difference  being 
probably  caused  by  the  fact  that  when  there  is  action  the 
above-mentioned  products  of  stimulation  are  consumed, 
while  in  stimulation  without  action  they  are  not  consumed 
and  must  be  eliminated  as  waste  products.  Now  these 
activating  substances  and  the  fuel  glycogen  may  be  con- 
sumed by  any  muscular  action  as  well  as  by  the  particular 
muscular  action  for  which  the  integration  and  consequent 
stimulation  were  made;  that  is,  if  one  were  provoked  to  such 
anger  that  he  felt  impelled  to  attack  the  object  of  his  anger, 
one  of  three  things  might  happen:  First,  he  might  perform 
no  physical  act  but  give  expression  to  the  emotion  of  anger; 
second,  he  might  engage  in  a  physical  struggle  and  completely 
satisfy  his  anger;  third,  he  might  immediately  engage  in 
violent  gymnastic  exercises  and  thus  consume  all  the  motor- 
producing  elements  mobilized  by  the  anger  and  thus  clarify 
his  body. 

In  these  premises  we  find  our  explanation  of  the  origin 
and  purpose  of  laughter  and  crying,  for  since  they  consist 
almost  wholly  of  muscular  exertion,  they  serve  precisely  such 
clarifying  purposes  as  would  be  served  by  the  gymnastic 
exercises  of  an  angry  man.  As  it  seems  to  me,  the  muscular 
action  of  laughter  clears  the  system  of  the  energizing  sub- 
stances which  have  been  mobilized  in  various  parts  of  the 
body  for  the  performance  of  other  actions  (Figs.  27  to  29). 
If  this  be  true,  the  first  question  that  presents  itself  is,  Why 


94 


THE    EMOTIONS 


Fig.  27. — The  facies  of  this  freckle-faced  boy  is  an  excellent  illustration 
of  the  expression  in  laughter  of  effervescent  and  infinitely  varied  possibilities 
of  motor  activity. 


Fig.  28.— The  snap-shot  was  taken  without  the  subject's  knowledge  and 
discloses  admirably  the  activation  of  the  facial  muscles  which  are  associated 
with  hearty  laughter. 


PAIN,    LAUGHTER,    AND    CRYING 


95 


is  the  respiratory  system  utilized  for  such  a  clarifying  pur- 
pose? Why  do  we  not  laugh  with  our  feet  and  hands  as 
well?  Were  laughter  expressed  with  the  hands,  the  monkey 
might  fall  from  the  tree  and,  if  by  the  feet,  man  might  fall 
to  the  ground.  He  would  at  least  be  ataxic.  In  fact, 
laughter  has  the  great  advantage  of  utilizing  a  group  of 
powerful    muscles   which    can    be    readily    spared    without 


Fig.  29. — The  laughter  of  this  boy  i.s  doubtless  the  outward  physical  ex- 
pression of  the  motor  activation  excited  by  the  anticipation  of  vigorous  out- 
door exercise.  When  he  begins  to  exercise,  this  laughter  will  diminish  or 
disappear. 


seriously  interfering  with  the  maintenance  of  posture. 
Laughter,  however,  is  only  one  form  of  muscular  action  which 
may  consume  the  fuel  thrown  into  the  blood  by  excitation. 
That  these  products  of  excitation  are  often  consumed  by 
other  motor  acts  than  laughter  is  frequently  seen  in  public 
meetings  when  the  stamping  of  feet  and  the  clapping  of 
hands  in  applause  gives  relief  to  the  excitation  (Fig.  30). 


96 


THE    EMOTIONS 


o 


pq 


a 
o 
O 


"o   -^ 
X    o 

^^ 
.2  -o 

o 

rn     fe: 

o    <s 
o    d 

c3   p 


-13 


PAIN,    LAUGHTER,    AND    CRYING  97 

Why  the  noise  of  laughter?  In  order  that  the  products  of 
excitation  may  be  quickly  and  completely  consumed,  the 
powerful  group  of  expiratory  muscles  must  have  some  re- 
sistance against  which  they  can  exert  themselves  strongly 
and  at  the  same  time  provide  for  adequate  respiratory  ex- 
change. The  intermittent  closure  of  the  epiglottis  serves 
this  purpose  admirably,  just  as  the  horizontal  bars  afford  the 
resistance  against  which  muscles  may  be  exercised.  The 
facial  muscles  are  not  in  use  for  other  purposes,  hence  their 
contractions  will  consume  a  little  of  the  fuel.  An  audience 
excited  by  the  words  of  an  impassioned  speaker  undergoes 
a  body-wide  stimulation  for  action,  all  of  which  may  be 
eliminated  by  laughter  or  by  applause  (Fig.  31). 

Let  us  test  this  hypothesis  by  some  practical  examples. 
The  first  is  an  incident  that  accidentally  occurred  in  our 
laboratory  during  experiments  on  fear  which  were  performed 
as  follows :  A  keen,  snappy  fox  terrier  was  completely  muzzled 
by  winding  a  broad  strip  of  adhesive  plaster  around  his  jaw 
so  as  to  include  all  but  the  nostrils.  When  this  aggressive 
little  terrier  and  the  rabbit  found  themselves  in  close  quar- 
ters each  animal  became  completely  governed  by  instinct; 
the  rabbit  crouched  in  fear,  while  the  terrier,  with  all  the 
ancestral  assurance  of  seizing  his  prey,  rushed  upon  the 
rabbit,  his  muzzle  always  glancing  off  and  his  attack  ending 
in  awkward  failure. 

This  experiment  was  repeated  many  times  and  each  time 
provoked  the  serious-minded  scientific  visitors  who  witnessed 
it  to  laughter.  Why?  Because  the  spectacle  of  a  savage 
little  terrier  rushing  upon  an  innocent  rabbit  as  if  to  mangle 
it  integrated  the  body  of  the  onlooker  with  a  strong  desire 
to  exert  muscular  action  to  prevent  the  cruelty.  This 
7 


98 


THE    EMOTIONS 


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■^  in 


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o  ^ 
o    a, 


#i^  #^4 


^^i--- 


B^^n 


&''-'  .^"l^"'*'*' 


-^    jH 


■Cife^i  »^ 


^  :2 


a 

X 

^^ — ^ 

.52 

>* 

^ 

^ 

T? 

^ 

O 

o 

o 

^ 

'■+3 

o 

o3 

TJ 
« 

O 

p 

KM 

T3 

o 

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X! 

o3 

-^  -s  ^^ 


-^  .g 


PAIN,    LAUGHTER,    AND    CRYING  99 

integration  caused  a  conversion  of  the  potential  energy  in  the 
brain-cells  into  kinetic  energy,  and  there  resulted  a  discharge 
into  the  blood-stream  of  activating  internal  secretions  for 
the  purpose  of  producing  muscular  action.  Instantly  and 
unexpectedly  the  danger  passed  and  the  preparation  for 
muscular  action  intended  for  use  in  the  protection  of  the 
rabbit  was  not  needed.  This  fuel  was  consumed  by  the 
neutral  muscular  action  of  laughter,  which  thus  afforded 
relief. 

A  common  example  of  the  same  nature  is  that  encountered 
on  the  street  when  a  pedestrian  shps  on  a  banana  peel  and, 
just  as  he  is  about  to  tumble,  recovers  his  equiUbrium.  The 
onlookers  secure  rehef  from  the  integration  to  run  to  his 
rescue  by  laughing.  On  the  other  hand,  should  the  same 
pedestrian  fall  and  fracture  his  skull  the  motor  integration 
of  the  onlookers  would  be  consumed  by  rendering  physical 
assistance — hence  there  would  be  no  laughter.  In  children 
almost  any  unexpected  phenomenon,  such  as  a  sudden 
"booing"  from  behind  a  door,  is  attended  by  laughter,  and 
in  hke  manner  the  kinetic  reaction  produced  by  the  innumer- 
able threats  of  danger  which  are  suddenly  averted,  a  breach 
of  the  conventions,  a  sudden  relief  from  acute  nervous 
tension;  a  surprise — indeed,  any  excitant  to  which  there  is 
no  predetermined  method  of  giving  a  physical  response — 
may  be  neutrahzed  by  the  excitation  of  the  mechanism  of 
laughter. 

In  the  same  way  the  laughter  excited  by  jokes  may  be 
explained.  An  analysis  of  a  joke  shows  that  it  is  composed 
of  two  parts — the  first,  in  which  is  presented  a  subject  that 
acts  as  a  stimulus  to  action,  and  the  second,  in  which  the 
story  turns  suddenly  so  that  the  stimulus  to  action  is  unex- 


100 


THE    EMOTIONS 


pectedly  withdrawn.  The  subject  matter  of  the  joke  affects 
each  hearer  according  to  the  type  of  stimuh  that  commonly 
excites  that  individual.  Hence  it  is  that  a  joke  may  convulse 
one  person  while  it  bores  another,  and  so  there  are  jokes  of 


Fig.  32. — A  Rtudy  in  Expression. 

The  camera  excited  resentment,  in  one  boy,  which  was  expressed  by  crying ; 

amusement  in  the  second;   while  the  third  was  indifferent. 


the  classes,  bankers'  jokes,  politicians'  jokes,  the  jokes  of 
professional  men,  of  the  plebeian,  of  the  artist,  etc.  If  the 
joke  fails,  the  integration  products  of  the  excitation  may  be 
used  in  physical  resentment  (Fig.  32), 

Another   type   of  laughter   is   that   associated   with   the 


PAIX,    LAUGHTER,    AND    CRYING  101 

ticklish  points  of  certain  parts  of  the  body,  the  soles  of  the 
feet  and  certain  parts  of  the  trunk  and  of  the  abdomen. 
The  excitation  of  the  ticklish  receptors,  like  pain,  compels 
self-defensive  motor  acts.  This  response  is  of  phylogenetic 
origin,  and  may  be  awakened  only  by  stimuli  which  are  too 
Hght  to  be  painful.  In  this  connection  it  is  of  interest  to 
note  that  a  superficial,  insect-like  contact  with  the  skin  rarely 
provokes  laughter,  and  that  the  tickling  of  the  nasal,  oral, 
and  pulmonary  tracts  does  not  produce  laughter.  The 
ticklish  points  that  cause  laughter  are  rather  deeply  placed, 
and  a  certain  type  of  physical  contact  is  required  to  con- 
stitute an  adequate  stimulus.  That  is,  the  contact  must 
arouse  a  phylogenetic  association  with  a  physical  struggle  or 
with  physical  exertion.  In  the  foot,  the  adequate  stimuli 
for  laughter  are  such  contacts  as  resemble  or  suggest  piercing 
bj'  stones  or  rough  objects.  The  intention  of  the  one  who 
tickles  must  be  known ;  if  his  intention  be  playful,  laughter 
results,  whereas  if  injury  be  intended,  then  an  effort  toward 
escape  or  defense  is  excited,  but  no  laughter.  If  deep  tick- 
ling of  the  ribs  is  known  to  be  mahcious,  it  will  excite  physical 
resentment  and  not  laughter.  Self-tickling  rarely  causes 
laughter  for  the  reason  that  auto-tickling  can  cause  only  a 
known  degree  of  stimulation,  so  that  there  results  no  ex- 
cessive integration  which  requires  relief  by  the  neutral 
muscular  activity  of  laughter.  In  fact,  one  never  sees 
purposeful  acts  and  laughter  associated.  According  to  its 
severity,  an  isolated  stimulus  causes  either  an  action  or 
laughter.  The  ticklish  points  in  our  bodies  were  probably 
developed  as  a  means  of  defense  against  serious  attacks  and 
of  escape  from  injurious  contacts. 

Anger,  fear,  and  grief  are  also  strong  excitants  and,  there- 


102  THE    EMOTIONS 

fore,  are  stimuli  to  motor  activity.  It  is  obvious  that  what- 
ever the  excitant  the  physico-chemical  action  of  the  brain 
and  the  ductless  glands  cannot  be  reversed — the  effect  of  the 
stimulus  cannot  be  recalled,  therefore  either  a  purposeful 
muscular  act  or  a  neutralizing  act  must  be  performed  or  else 
the  liberated  energy  must  smoulder  in  the  various  parts  of 
the  body. 

It  is  on  this  hypothesis  that  the  origin  and  the  purpose  of 
laughter  and  crying  may  be  understood.  Even  a  super- 
ficial analysis  of  the  phenomena  of  both  laughter  and  crying 
show  them  to  be  without  any  external  motor  purpose;  the 
respiratory  mechanism  is  intermittently  stimulated  and  in- 
hibited; and  the  shoulder  and  arm  muscles,  indeed,  many 
muscles  of  the  trunk  and  the  extremities  are,  as  far  as  any 
external  design  is  concerned,  purposelessly  contracted  and 
released  until  the  kinetic  energy  mobilized  by  excitation  is 
utilized.  During  this  time  the  facial  expression  gives  the 
index  to  the  mental  state. 

Crying,  like  laughter,  is  always  preceded  by  a  stimulation 
to  some  motor  action  which  may  or  may  not  be  performed 
(Figs.  33  and  34).  If  a  mother  is  anxiously  watching  the 
course  of  a  serious  illness  of  her  child  and  if,  in  caring  for  it, 
she  is  stimulated  to  the  utmost  to  perform  motor  acts,  she  will 
continue  in  a  state  of  motor  tenseness  until  the  child  recovers 
or  dies.  If  relief  is  sudden,  as  in  the  crisis  of  pneumonia, 
and  the  mother  is  not  exhausted,  she  will  easily  laugh;  if 
tired,  she  may  cry.  If  death  occurs,  the  stimulus  to  motor 
acts  is  suddenly  withdrawn  and  she  then  cries  aloud,  and 
performs  many  motor  acts  as  a  result  of  the  intense  stimula- 
tion to  motor  activity  which  is  no  longer  needed  in  the 
physical  care  of  her  child.     With  this  clue  we  can  find  the 


Fig.  33. — Laughing  Child. 

This  baby  is  trying  to  seize  the  toy  with  which  his  sister  is  playing  and  finds 

reUef  in  continuous  activation. 

103 


;^ 


( 


Fig.  34. — Crying  Child. 


That  crying  is  the  result  of  stimulation  to  motor  activity  is  well  shown  by 
these  photographs.  In  A  the  baby's  bottle  is  being  held  just  beyond  his 
reach,  and  the.'position  of  his  hands  shows  that  he  is  ready  to  take  it,  but  as  it 
is  not  given  to  him,  his  activation  finds  expression  in  moderate  crying. 

In  B  the  bottle  has  been  carried  out  of  his  sight,  the  activation  has  in- 
creased and  is  expressed  by  increased  crying  and  by  rapid  arm  motions. 

104 


PAIN,    LAUGHTER,    AND    CRYING 


105 


explanation  of  many  phenomena.  We  can  understand  why 
laughter  and  crying  are  so  frequently  interchangeable;  why 
they  often  blend  and  why  either  gives  a  sense  of  relief;   we 


X 


Fig.  35. — Sleeping  Child. 
The  energy  expended  in  his  waking  activities  is  being  restored  in  sleep.     Com- 
pare with  Figs.  33  and  34. 


can  understand  why  either  laughter  or  crjang  can  come  only 
when  the  issue  that  causes  the  integration  is  determined; 
we  can  understand  the  extraordinary  tendency  to  laughter 
that  discloses  the  unspoken  sentiments  of  love;    we   can 


106  THE    EMOTIONS 

understand  the  tears  of  the  woman  when  she  receives  a  pro- 
posal of  marriage  from  the  man  she  loves;  we  can  under- 
stand why  any  averted  circumstance,  such  as  a  threatened 
breach  of  the  conventions,  which  would  have  led  to  embar- 
rassment or  humiliation,  leads  to  a  tendency  to  laughter; 
and  why  the  recital  of  heroic  deeds  by  association  leads  to 
tears.  On  the  other  hand,  under  the  domination  of  acute 
diseases,  of  acute  fear,  or  of  great  exhaustion,  there  is  usually 
neither  laughter  nor  crying  because  the  nervous  system  is 
under  the  control  of  a  dominating  influence  as  a  result  of 
which  the  body  is  so  exhausted  that  the  excess  of  energy 
which  alone  can  produce  laughing  or  crying  is  lacking. 

A  remarkable  study  of  the  modification  of  laughter  and 
crying  by  disease  is  found  in  that  most  interesting  of  diseases 
— exophthalmic  goiter.  In  this  disease  there  is  a  low  thresh- 
old to  all  stimuli.  That  the  very  motor  mechanism  of  which 
we  have  been  speaking  is  involved,  is  shown  by  an  enormous 
increase  in  its  activity.  There  is  also  an  increase  in  the  size 
of  certain  at  least  of  the  activating  glands — the  thyroid  and 
the  adrenals  are  enlarged  and  overactive  and  the  glycogen- 
producing  function  of  the  liver  is  stimulated.  The  most 
striking  phenomenon  of  this  disease,  however,  is  the  remark- 
able lowering  of  the  brain  thresholds  to  stimuli.  In  other 
words,  in  Graves'  disease  the  nervous  system  and  the  acti- 
vating glands — the  entire  motor  mechanism — are  in  an 
exalted  state  of  activity. 

If  this  be  true,  then  these  patients  should  exhibit  behavior 
precisely  contrary  to  that  of  those  suffering  from  acute  in- 
fection, that  is,  they  should  be  constantly  clearing  their 
systems  of  these  superabundant  energizing  materials  by 
crying  or  laughing,  and  this  is  precisely  what  happens — the 


PAIN,    LAUGHTER,    AND    CRYING  107 

flood-gates  of  tears  are  open  much  of  the  tune  in  Graves' 
disease — a  disease  of  the  emotions. 

We  have  already  interpreted  pain  as  a  phenomenon  of 
motor  activity.  WTien  pain  does  not  lead  to  muscular  activ- 
ity it  therefore  frequently  leads  to  crying  or  to  moaning,  just 
as  tickling,  which  is  equally  an  incentive  to  motor  activity, 
results  in  laughter  if  it  does  not  find  full  expression  in  action. 

From  the  foregoing  we  infer  that  pain,  the  intense  motor 
response  to  tickhng,  and  emotional  excitation  are  all  primi- 
tive biologic  reactions  for  the  good  of  the  individual,  and 
that  all  have  their  origin  in  the  operation  of  the  great  laws 
of  evolution.  If  to  this  inference  we  add  the  physiologic 
dictum  that  the  nervous  system  always  acts  as  a  whole,  and 
that  it  can  respond  to  but  one  stimulus  at  a  time,  we  can 
easily  understand  that  while  diverse  causes  may  integrate 
the  nervous  system  for  a  specific  action,  if  the  cause  be 
suddenly  removed,  then  the  result  of  the  integration  of  the 
nervous  system  may  be,  not  a  specific  action,  but  an  unde- 
signed muscular  action,  such  as  crying  or  laughter.  Hence 
it  is  that  laughter  and  crying  may  be  evoked  by  diverse 
exciting  causes.  The  intensity  of  the  laughter  or  of  the  cry- 
ing depends  upon  the  intensity  of  the  stimulus  and  the  dy- 
namic state  of  the  individual. 

The  hnking  together  of  these  apparently  widely  separated 
phenomena  by  the  simple  law  of  the  discharge  of  energy  by 
association  perhaps  explains  the  association  of  an  abnormal 
tendency  to  tears  with  an  abnormally  low  threshold  for  pain 
(Fig.  36).  In  the  neurasthenic,  tears  and  pain  are  produced 
with  abnormal  faciUty.  Hence  it  is  that,  if  a  patient  about 
to  undergo  a  surgical  operation  is  in  a  state  of  fear  and  dread 
before  the  operation,  the  threshold  to  all  stimuli  is  lowered. 


108  THE    EMOTIONS 

and  this  lowered  threshold  will  continue  throughout  the 
operation,  even  under  inhalation  anesthesia,  because  the 
stimulus  produced  by  cutting  sensitive  tissue  is  transmitted 
to  the  brain  just  as  readily  as  if  the  patient  were  not  anes- 


FiG.  36. — Photo  of  homesick  patient  in  hospital  whose  brain  threshold  had 
been  so  lowered  that  the  slightest  stimulus  resulted  in  tears. 


thetized.  In  like  manner,  the  brain  may  be  sensitized  by 
the  administration  of  large  doses  of  thyroid  extract  prior  to 
operation,  the  threshold  to  injury  in  such  a  case  continuing 
to  be  low  to  traumatic  stimuli  even  under  anesthesia.  Under 
the  sensitizing  influences  of  thyroid  extract  or  of  Graves' 


PAIN,    LAUGHTER,    AND    CRYING  109 

disease  the  effect  of  an  injury,  of  an  operation,  or  of  emo- 
tional excitation  is  heightened.  The  extent  to  which  the 
threshold  to  pain  or  to  any  other  excitant  is  affected  by 
Graves'  disease  is  illustrated  by  the  almost  fatal  reaction 
which  I  once  saw  result  from  the  mere  pricking  with  a  hypo- 
dermic needle  of  a  patient  with  this  disease.  As  the  result 
of  a  visit  from  a  friend,  the  pulse-rate  of  a  victim  of  this 
disease  may  increase  twenty  beats  and  his  temperature  rise 
markedly.  I  have  seen  the  mere  suggestion  of  an  operation 
produce  collapse.  As  the  brain  is  thus  remarkably  sensi- 
tized in  Graves'  disease,  we  find  that  in  these  patients 
laughter,  crying,  emotional  disturbances,  and  surgical  shock 
are  produced  with  remarkable  facility. 

I  hope  that  even  this  admittedly  crude  and  imperfect 
consideration  of  this  subject  will  suggest  the  possibility  of 
establishing  a  practical  viewpoint  as  to  the  origin  and  pur- 
pose of  pain,  of  tickling,  and  of  such  expressions  of  emotion 
as  laughter  and  crying,  and  that  it  may  help  us  to  under- 
stand their  significance  in  health  and  in  disease. 


THE   RELATION   BETWEEN   THE   PHYSICAL    STATE   OF 
THE  BRAIN-CELLS  AND  BRAIN  FUNCTIONS— EX- 
PERIMENTAL AND  CLINICAL* 

The  brain  in  all  animals  (including  man)  is  but  the  clearing- 
house for  reactions  to  environment,  for  animals  are  essen- 
tially motor  or  neuromotor  mechanisms,  composed  of  many 
parts,  it  is  true,  but  integrated  by  the  nervous  system. 
Throughout  the  phylogenetic  history  of  the  race  the  stimuli 
of  environment  have  driven  this  mechanism,  whose  seat  of 
power — the  battery — is  the  brain. 

Since  all  normal  life  depends  upon  the  response  of  the 
brain  to  the  daily  stimuli,  we  should  expect  in  health,  as 
well  as  in  disease,  to  find  modifications  of  the  functions  and 
the  physical  state  of  the  component  parts  of  this  central 
battery — the  brain-cells.  Although  we  must  believe,  then, 
that  every  reaction  to  stimuli,  however  slight,  produces  a 
corresponding  change  in  the  brain-cells,  yet  there  are  cer- 
tain normal,  that  is,  non-diseased,  conditions  which  produce 
especially  striking  changes.  The  cell  changes  due  to  the 
emotions,  for  example,  are  so  similar,  and  in  extreme  con- 
ditions approach  so  closely  to  the  changes  produced  by  dis- 
ease, that  it  is  impossible  to  say  where  the  normal  ceases  and 
the  abnormal  begins. 

In  view  of  the  similarity  of  brain-cell  changes  it  is  not 
strange  that  in  the  clinic,  as  well  as  in  daily  life,  we  are  con- 
fronted constantly  by  outward  manifestations  which  are  so 
nearly  identical  that  the  true  underlying  cause  of  the  condi- 

*  Address  before  The  American  Philosophical  Society,  April  18,  1913. 

Ill 


112  THE    EMOTIONS  g, 

tion  in  any  individual  case  is  too  often  overlooked  or  mis- 
understood. In  our  laboratory  experiments  and  in  our 
clinical  observations  we  have  found  that  exhaustion  produced 
by  intense  emotion,  prolonged  physical  exertion,  insomnia, 
intense  fear,  certain  toxemias,  hemorrhage,  and  the  con- 
dition commonly  denominated  surgical  shock,  produce 
similar  outward  manifestations  and  identical  brain-cell 
changes. 

It  is,  therefore,  the  purpose  of  this  paper  to  present  the 
definite  results  of  laboratory  researches  which  show  certain 
relations  between  alterations  in  brain  functions  and  physical 
changes  in  the  brain-cells. 

Fear. — -Our  experiments  have  shown  that  the  brain-cell 
changes  due  to  fear  may  be  divided  into  two  stages:  First, 
that  of  hyperchromatism — stimulation;  second,  that  of 
hypochromatism — exhaustion  (Figs.  5  and  13).  Hyperchro- 
matism was  shown  only  in  the  presence  of  the  activating 
stimuli  or  within  a  very  short  time  after  they  had  been  re- 
ceived. This  state  gradually  changed  until  the  period  of 
maximum  exhaustion  was  reached — about  six  hours  later. 
Then  a  process  of  reconstruction  began  and  continued  until 
the  normal  state  was  again  reached. 

Fatigue. — Fatigue  from  overexertion  produced  in  the 
brain-cells  like  changes  to  those  produced  by  fear,  these 
changes  being  proportional  to  the  amount  of  exertion  (Fig. 
4).  In  the  extreme  stage  of  exhaustion  from  this  cause  we 
found  that  the  total  quantity  of  Nissl  substance  was  enor- 
mously reduced.  When  the  exertion  was  too  greatly  pro- 
longed, it  took  weeks  or  months  for  the  cells  to  be  restored 
to  their  normal  condition.  We  have  proved,  therefore,  that 
in  exhaustion  resulting  from  emotion  or  from  physical  work 


BRAIN-CELLS    AND    BRAIN    FUNCTIONS  113 

a  certain  number  of  the  brain-cells  are  permanently  lost. 
This  is  the  probable  explanation  of  the  fact  that  an  athlete 
or  a  race-horse  trained  to  the  point  of  highest  efficiency  can 
reach  his  maximum  record  but  once  in  his  life.  Under 
certain  conditions,  however,  it  is  possible  that,  though  some 
chromatin  is  forever  lost,  the  remainder  may  be  so  remark- 
ably developed  that  for  a  time  at  least  it  will  compensate 
for  that  which  is  gone. 

Hemorrhage. — The  loss  of  blood  from  any  cause,  if 
sufficient  to  reduce  the  blood-pressure,  will  occasion  a  change 
in  the  brain-cells,  provided  that  the  period  of  hypotension 
lasts  for  more  than  five  minutes.  This  time  limit  is  a  safe- 
guard against  permanent  injury  from  the  temporary  hypo- 
tension which  causes  one  to  faint.  If  the  hemorrhage  be 
long  continued  and  the  blood-pressure  be  low,  there  will  be  a 
permanent  loss  of  some  of  the  brain-cells.  This  explains 
why  an  individual  who  has  suffered  from  a  prolonged  hem- 
orrhage will  never  again  be  restored  to  his  original  powers. 

Drugs. — According  to  their  effect  upon  the  brain-cells, 
drugs  may  be  divided  into  three  classes:  First,  those  that 
stimulate  the  brain-cells  to  increased  activity,  as  strychnin 
(Fig.  37);  second,  those  that  chemically  destroy  the  brain- 
cells,  as  alcohol  and  iodoform  (Figs.  38  and  39) ;  third,  those 
that  suspend  the  functions  of  the  cells  without  damaging 
them,  as  nitrous  oxid,  ether,  morphin.  Our  experiments  have 
shown  that  the  brain-cell  changes  induced  by  drugs  of  the 
first  class  are  precisely  the  same  as  the  cycle  of  changes  pro- 
duced by  the  emotions  and  by  physical  activity.  We  have 
found  that  strychnin,  according  to  the  dosage,  causes  con- 
vulsions ending  in  exhaustion  and  death ;  excitation  followed 
by  lassitude;    stimulation  without  notable  after-results;    or 


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after  Single  Dose  of  Strychnin. 


C,  Section  of  Cerebellum  of  Dog  after 
Repeated  Doses  of  Strychnin. 


Fig.  37. — Brain-cells  Showing  Stage  of  Hyperchromatism  Followed  by 
Chromatolysis  Resl'lting  from  the  Continuation  of  the  Stimulus. 
(Camera  lucida  drawings.) 

114 


BRAIN-CELLS    AND    BRAIN    FUNCTIONS 


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116  THE    EMOTIONS 

increased  mental  tone;  while  the  brain-cells  accurately 
display  these  physiologic  alterations  in  proportional  hyper- 
chromatism  in  the  active  stages,  and  proportional  chroma- 
tolysis  in  the  stages  of  reaction.  The  biologic  and  thera- 
peutic application  of  this  fact  is  as  obvious  as  it  is  im- 
portant. 

In  our  experiments,  alcohol  in  large  and  repeated  dosage 
caused  marked  morphologic  changes  in  the  brain-cells  which 
went  as  far  even  as  the  destruction  of  some  of  the  cells  (Fig. 
39).  Ether,  on  the  other  hand,  even  after  five  hours  of 
administration,  produced  no  observable  destructive  changes 
in  the  brain-cells. 

The  effect  of  iodoform  was  peculiarly  interesting,  as  it 
was  the  only  drug  that  produced  a  rise  of  temperature.  Its 
observed  effect  upon  the  brain-cells  was  that  of  wide-spread 
destruction. 

Infections. — In  every  observation  regarding  the  effect  of 
pyogenic  infections  on  dogs  and  on  man  we  found  that  they 
caused  definite  and  demonstrable  lesions  in  certain  cells  of 
the  nervous  system,  the  most  marked  changes  being  in  the 
cortex  and  the  cerebellum  (Fig.  40).  For  example,  in  fatal 
infections  resulting  from  bowel  obstruction,  in  peritonitis, 
and  in  osteomyelitis,  the  real  lesion  is  in  the  brain-cells. 
We  may,  therefore,  reasonably  conclude  that  the  lassitude, 
the  diminished  mental  power,  the  excitability,  irritability, 
restlessness,  delirium,  and  unconsciousness  which  may  be 
associated  with  acute  infections,  are  due  to  physical  changes 
in  the  brain-cells. 

Graves'  Disease. — In  Graves'  disease  the  brain-cells 
show  marked  changes  which  are  apparently  the  same  as 
those  produced  by  overwork,  by  the  emotions,  and  by  strych- 


BEAIN-CELLS    AND    BRAIN    FUNCTIONS 


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Fig.  39A.  —  Section  of  Human 
Cerebellum — Normal  (After 
Accidental  Death). 


Fig.  39B.  —  Section  of  Human 
Cerebellum,  Showing  Ef- 
fects OF  Alcohol  (After  Death 
FROM  Delirium  Tremens). 
(Camera  lucida  drawings.) 


118 


THE    EMOTIONS 


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BRAIN-CELLS    AND    BRAIN    FUNCTIONS  119 

nin.  In  the  postmortem  examination  of  one  advanced  case 
it  was  found  that  a  large  number  of  brain-cells  were  disinte- 
grated beyond  the  power  of  recuperation,  even  had  the 
patient  lived.  This  is  undoubtedly  the  reason  why  a  severe 
case  of  exophthalmic  goiter  sustains  a  permanent  loss  of 
brain  power. 

Insomnia. — The  brains  of  rabbits  which  had  been  kept 
awake  for  one  hundred  hours  showed  precisely  the  same 
changes  as  those  shown  in  physical  fatigue,  strychnin  poison- 
ing, and  exhaustion  from  emotional  stimulation.  Eight 
hours  of  continuous  sleep  restored  all  the  cells  except  those 
that  had  been  completely  exhausted.  This  will  explain  the 
permanent  ill  effect  of  long-continued  insomnia;  that  is, 
long-continued  insomnia  permanently  destroys  a  part  of 
the  brain-cells  just  as  do  too  great  physical  exertion,  certain 
drugs,  emotional  strain,  exophthalmic  goiter,  and  hemorrhage. 
We  found,  however,  that  if,  instead  of  natural  sleep,  the 
rabbits  were  placed  for  the  same  number  of  hours  under 
nitrous  oxid  anesthesia,  not  only  did  the  brain-cells  recover 
from  the  physical  deterioration,  but  that  90  per  cent,  of  them 
became  hyperchromatic.  This  gives  us  a  possible  clue  to 
the  actual  chemical  effect  of  sleep.  For  since  nitrous  oxid 
owes  its  anesthetic  effect  to  its  influence  upon  oxidation, 
we  may  infer  that  sleep  also  retards  the  oxidation  of  the 
cell  contents.  If  this  be  true,  then  it  is  probable  that  inha- 
lation anesthetics  exert  their  peculiar  influence  upon  that 
portion  of  the  brain  through  which  sleep  itself  is  produced. 
If  nitrous  oxid  anesthesia  and  sleep  are  chemically  identical, 
then  we  have  a  further  clue  to  one  of  the  primary  mechan- 
isms of  life  itself;  and  as  a  practical  corollary  one  might  be 
able  to  produce  artificial  sleep  which  would  closely  resemble 


120  THE    EMOTIONS 

normal  sleep,  but  which  would  have  this  advantage,  that  by 
using  an  anesthetic  which  interferes  with  oxidation  the  brain- 
cells  might  be  reconstructed  after  physical  fatigue,  after 
emotional  strain,  or  after  the  depression  of  disease. 

In  the  case  of  the  rabbit  in  which  nitrous  oxid  was  sub- 
stituted for  sleep,  the  appearance  of  the  brain-cells  resembled 
that  in  but  one  other  group  experimentally  examined — the 
brain-cells  of  hibernating  woodchucks. 

Insanity. — Our  researches  have  shown  that  in  the  course 
of  a  fatal  disease  and  in  fatal  exhaustion,  however  produced, 
death  does  not  ensue  until  there  is  marked  disorganization  of 
the  brain  tissue.  In  the  progress  of  disease  or  exhaustion 
one  may  see  in  different  patients  every  outward  manifesta- 
tion of  mental  deterioration,  manifestations  which,  in  a 
person  who  does  not  show  any  other  sign  of  physical  disease, 
mark  him  as  insane.  Take,  for  example,  the  progressive 
mental  state  of  a  brilliant  scholar  suffering  from  typhoid 
fever.  On  the  first  day  of  the  gradual  onset  of  the  disease  he 
would  notice  that  his  mental  power  was  below  its  maximum 
efficiency;  on  the  second  he  would  notice  a  further  deteriora- 
tion, and  so  the  mental  effect  of  his  disease  would  progress 
until  he  would  find  it  impossible  to  express  a  thought  or  to 
make  a  deduction.  No  one  can  be  philanthropic  with 
jaundice;  no  one  suffering  from  Graves'  disease  can  be 
generous ;  no  mental  process  is  possible  in  the  course  of  the 
acute  infectious  diseases.  Just  prior  to  death  from  any 
cause  every  one  is  in  a  mental  state  which,  if  it  could  be  con- 
tinued, would  cause  that  individual  to  be  judged  insane. 
If  the  delirium  that  occurs  in  the  course  of  certain  diseases 
should  be  continued,  the  patient  would  be  judged  insane. 
In  severe    cases   of  Graves'   disease  the  patient  is  insane. 


BRAIN-CELLS    AND    BRAIN    FUNCTIONS  121 

Individuals  under  overwhelming  emotion  may  be  tempo- 
rarily insane.  Every  clinician  has  seen  great  numbers  of 
cases  in  which  insanity  is  a  phase  of  a  disease,  of  an  injury, 
or  of  an  emotion.  The  stage  of  excitation  in  anesthesia  is 
insanity.  The  only  difference  between  what  is  convention- 
ally called  insanity  and  the  fleeting  insanity  of  the  sick  and 
the  injured  is  that  of  time.  We  may  conclude,  therefore, 
what  must  be  the  brain-picture  of  the  person  who  is  per- 
manently insane.  This  a  priori  reasoning  is  all  that  is 
possible,  since  the  study  of  the  brain  in  the  insane  has  thus 
far  been  confined  to  the  brains  of  those  who  have  died  of 
some  disease.  And  it  is  impossible  to  say  which  changes 
have  been  produced  by  the  fatal  disease,  and  which  by  the 
condition  which  produced  the  insanity.  The  only  logical 
way  by  which  to  investigate  the  physical  basis  of  insanity 
would  be  to  make  use  of  the  very  rare  opportunities  of 
studying  the  brains  of  insane  persons  who  have  died  in 
accidents. 

Our  experiments  have  proved  conclusively  that  whether 
we  call  a  person  fatigued  or  diseased,  the  brain-cells  undergo 
physical  deterioration,  accompanied  by  loss  of  mental  power 
(Figs.  40  to  43).  Even  to  the  minutest  detail  we  can  show  a 
direct  relationship  between  the  physical  state  of  the  brain - 
cells  and  the  mental  power  of  the  individual,  that  is,  the 
physical  power  of  a  person  goes  pari  passu  with  his  mental 
power.  Indeed,  it  is  impossible  to  conceive  how  any  mental 
action,  however  subtle,  can  occur  without  a  corresponding 
change  in  the  brain-cells.  It  is  possible  now  to  measure  only 
the  evidences  of  the  effects  on  the  brain-cells  of  gross  and 
violent  mental  activity.  At  some  future  time  it  will  doubt- 
less be  possible  so  to  refine  the  technic  of  brain-cell  examina- 


122 


THE    EMOTIONS 


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BRAIX-CELLS    AXD    BRAIN    FUNCTIONS 


123 


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z  fa  o 

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124 


THE    EMOTIONS 


2 


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BRAIN-CELLS    AND    BRAIN    FUNCTIONS  125 

tions  that  more  subtle  changes  may  be  measured.  Never- 
theless, with  the  means  at  our  disposal  we  have  shown 
already  that  in  all  the  conditions  which  we  have  studied  the 
cells  of  the  cortex  show  the  greatest  changes,  and  that  loss 
of  the  higher  mental  functions  invariably  accompanies  the 
cell  deterioration. 


A  MECHANISTIC  VIEW  OF  PSYCHOLOGY* 

Traditional  religion,  traditional  medicine,  and  traditional 
psychology  have  insisted  upon  the  existence  in  man  of  a  tri- 
une nature.  Three  "ologies"  have  been  developed  for  the 
study  of  each  nature  as  a  separate  entity — body,  soul,  and 
spirit — physiology,  psychology,  theology;  physician,  psy- 
chologist, priest.  To  the  great  minds  of  each  class,  from  the 
days  of  Aristotle  and  Hippocrates  on,  there  have  come 
glimmerings  of  the  truth  that  the  phenomena  studied  under 
these  divisions  were  interrelated.  Always,  however,  the 
conflict  between  votaries  of  these  sciences  has  been  sharp, 
and  the  boundary  lines  between  them  have  been  constantly 
changing.  Since  the  great  discoveries  of  Darwin,  the  zool- 
ogist, biologist,  and  physiologist  have  joined  hands,  but  still 
the  soul-body-spirit  chaos  has  remained.  The  physician 
has  endeavored  to  fight  the  gross  maladies  which  have  been 
the  result  of  disordered  conduct;  the  psychologist  has 
reasoned  and  experimented  to  find  the  laws  governing  con- 
duct; and  the  priest  has  endeavored  by  appeals  to  an  un- 
known god  to  reform  conduct. 

The  great  impulse  to  a  deeper  and  keener  study  of  man's 
relation,  not  only  to  man,  but  to  the  whole  animal  creation, 
which  was  given  by  Darwin,  has  opened  the  way  to  the  study 
of  man  on  a  different  basis.  Psychologists,  physicians,  and 
priests  are  now  joining  hands  as  never  before  in  the  great 

*  Address  delivered  before  Sigma  Xi,  Case  School  of  Science,  Cleveland, 
Ohio,  May  27,  1913,  and  published  in  Science,  August  29,  1913. 

127 


128  THE    EMOTIONS 

world-wide  movement  for  the  betterment  of  man.  The  new 
science  of  sociology  is  combining  the  functions  of  all  three,  for 
priest,  physician,  and  psychologist  have  come  to  see  that  man 
is  in  large  measure  the  product  of  his  environment. 

My  thesis  to-night,  however,  will  go  beyond  this  common 
agreement,  for  I  shall  maintain,  not  that  man  is  in  large 
measure  the  product  of  his  environment,  but  that  environ- 
ment has  been  the  actual  creator  of  man;  that  the  old  division 
between  body,  soul,  and  spirit  is  non-existent;  that  man  is 
a  unified  mechanism  responding  in  every  part  to  the  adequate 
stimuli  given  it  from  without  by  the  environment  of  the 
present  and  from  within  by  the  environment  of  the  past,  the 
record  of  which  is  stored  in  part  in  cells  throughout  the 
mechanism,  but  especially  in  its  central  battery — the  brain. 
I  postulate  further  that  the  human  body  mechanism  is 
equipped,  first,  for  such  conflict  with  environment  as  will 
tend  to  the  preservation  of  the  individual;  and,  second,  for 
the  propagation  of  the  species,  both  of  these  functions 
when  most  efficiently  carried  out  tending  to  the  upbuilding 
and  perfection  of  the  race. 

Through  the  long  ages  of  evolution  the  human  mechanism 
has  been  slowly  developed  by  the  constant  changes  and 
growth  of  its  parts  which  have  resulted  from  its  continual 
adaptation  to  its  environment.  In  some  animals  the  pro- 
tection from  too  rough  contact  with  surroundings  was  se- 
cured by  the  development  of  an  outside  armor;  in  others 
noxious  secretions  served  the  purposes  of  defense,  but  such 
devices  as  these  were  not  suitable  for  the  higher  animals  nor 
for  the  diverse  and  important  functions  of  the  human  race. 
The  safety  of  the  higher  animals  and  of  man  had  to  be  pre- 
served by  some  mechanism  by  means  of  which  they  could 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  129 

become  adapted  to  a  much  wider  and  more  complex  environ- 
ment, the  dominance  over  which  alone  gives  them  their 
right  to  be  called  ''superior  beings."  The  mechanism  by 
the  progressive  development  of  which  living  beings  have  been 
able  to  react  more  and  more  effectually  to  their  environment 
is  the  central  nervous  system,  which  is  seen  in  one  of  its 
simplest  forms  in  motor  plants,  such  as  the  sensitive  plant 
and  the  Venus  fly-trap,  and  in  its  highest  development  only 
in  the  sanest,  healthiest,  happiest,  and  most  useful  men. 

The  essential  function  of  the  nervous  system  was  primarily 
to  secure  some  form  of  motor  activity,  first  as  a  means  of 
securing  food,  and  later  as  a  means  of  escaping  from  enemies 
and  to  promote  procreation.  Activities  for  the  preservation 
of  the  individual  and  of  the  species  were  and  are  the  only 
purposes  for  which  the  body  energy  is  expended.  The 
central  nervous  system  has  accordingly  been  developed  for 
the  purpose  of  securing  such  motor  activities  as  will  best 
adapt  the  individuals  of  a  species  for  their  self-preservative 
conflict  with  environment. 

It  is  easy  to  appreciate  that  the  simplest  expressions  of 
nerve  response — the  reflexes — are  motor  in  character,  but  it 
is  difficult  to  understand  how  such  intangible  reactions  as 
love,  hate,  poetic  fancy,  or  moral  inhibition  can  be  also  the 
result  of  the  adaptation  to  environment  of  a  distinctively 
motor  mechanism.  We  expect,  however,  to  prove  that  so- 
called  ''psychic"  states  as  well  as  the  reflexes  are  products 
of  adaptation;  that  they  occur  automatically  in  response  to 
adequate  stimuh  in  the  environment ;  that,  like  the  reflexes, 
they  are  expressions  of  motor  activity,  which,  although  in- 
tangible and  unseen,  in  turn  incite  to  activity  the  units  of 
the  motor  mechanism  of  the  body;  and  finally,  that  any 
9 


130  THE    EMOTIONS 

''psychic"  condition  results  in  a  definite  depletion  of  the 
potential  energy  in  the  brain-cells  which  is  proportionate  to 
the  muscular  exertion  of  which  it  is  the  representative. 

That  this  nerve  mechanism  may  effectively  carry  out  its 
twofold  function,  first,  of  self-adaptation  to  meet  adequately 
the  increasingly  complicated  stimuli  of  environment;  and 
second,  of  adapting  the  motor  mechanism  to  respond  ade- 
quately to  its  demands,  there  have  been  implanted  in  the 
body  numerous  nerve  ceptors — some  for  the  transmission  of 
stimuh  harmful  to  the  mechanism — nociceptors;  some  of  a 
beneficial  character — beneceptors;  and  still  others  more  highly 
specialized,  which  partake  of  the  nature  of  both  bene-  and 
nociceptors — the  distance  ceptors,  or  special  senses. 

A  convincing  proof  that  environment  has  been  the  creator 
of  man  is  seen  in  the  absolute  adaptation  of  the  nociceptors 
as  manifested  in  their  specific  response  to  adequate  stimuli, 
and  in  their  presence  in  only  those  parts  of  the  body  which 
throughout  the  history  of  the  race  have  been  most  exposed 
to  harmful  contacts.  We  find  they  are  most  numerous  in 
the  face,  the  neck,  the  abdomen,  the  hands,  and  the  feet; 
while  in  the  back  they  are  few  in  number,  and  within  the 
bony  cavities  they  are  lacking. 

Instances  of  the  specific  responses  made  by  the  nociceptors 
might  be  multiplied  indefinitely.  Sneezing,  for  example,  is 
a  specific  response  made  by  the  motor  mechanism  to  stimula- 
tion of  nociceptors  in  the  nose,  while  stimulation  of  the 
larynx  does  not  produce  a  sneeze,  but  a  cough;  stimulation 
of  the  nociceptors  of  the  stomach  does  not  produce  cough, 
but  vomiting;  stimulation  of  the  nociceptors  of  the  intes- 
tine does  not  produce  vomiting,  but  increased  peristaltic 
action.     There  are  no  nociceptors  misplaced;   none  wasted; 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  131 

none  that  do  not  make  an  adequate  response  to  adequate 
stimulation. 

Another  most  significant  proof  that  the  environment  of 
the  past  has  been  the  creator  of  the  man  of  to-day  is  seen  in 
the  fact  that  man  has  added  to  his  environment  certain 
factors  to  which  adaptation  has  not  as  yet  been  made.  For 
example,  heat  is  a  stimulus  which  has  existed  since  the  days 
of  prehistoric  man,  while  the  a--ray  is  a  discovery  of  to-day; 
to  heat,  the  nociceptors  produce  an  adequate  response;  to 
the  x-ray  there  is  no  response.  There  was  no  weapon  in  the 
prehistoric  ages  which  could  move  at  the  speed  of  a  bullet 
from  the  modern  rifle,  therefore,  while  slow  penetration  of 
the  tissues  produces  great  pain  and  muscular  response,  there 
is  no  response  to  the  swiftly  moving  bullet. 

The  response  to  contact  stimuli  then  depends  always  on 
the  presence  of  nociceptors  in  the  affected  part  of  the  body 
and  to  the  type  of  the  contact.  Powerful  response  is  made 
to  crushing  injurj^  by  environmental  forces;  to  such  injuring 
contacts  as  resemble  the  impacts  of  fighting;  to  such  tearing 
injuries  as  resemble  those  made  by  teeth  and  claws  (Fig.  9). 
On  the  other  hand,  the  sharp  division  of  tissue  by  cutting 
produces  no  adaptive  response;  indeed,  one  might  imagine 
that  the  body  could  be  cut  to  pieces  by  a  superlatively  sharp 
knife  applied  at  tremendous  speed  without  material  adaptive 
response. 

These  examples  indicate  how  the  history  of  the  phylogen- 
etic  experiences  of  the  human  race  may  be  learned  by  a 
study  of  the  position  and  the  action  of  the  nociceptors,  just 
as  truly  as  the  study  of  the  arrangement  and  variations  in 
the  strata  of  the  earth's  crust  discloses  to  us  geologic  history. 

These  adaptive  responses  to  stimuli  are  the  result  of  the 


132  THE    EMOTIONS 

action  of  the  brain-cells,  which  are  thus  continually  played 
upon  by  the  stimuli  of  environment.  The  energy  stored  in 
the  brain-cells  in  turn  activates  the  various  organs  and  parts 
of  the  body.  If  the  environmental  impacts  are  repeated 
with  such  frequency  that  the  brain-cells  have  no  time  for 
restoration  between  them,  the  energy  of  the  cells  becomes 
exhausted  and  a  condition  of  shock  results.  Every  action 
of  the  body  may  thus  be  analyzed  into  a  stimulation  of 
ceptors,  a  consequent  discharge  of  brain-cell  energy,  and  a 
final  adaptive  activation  of  the  appropriate  part.  Walking, 
running,  and  their  modifications  constitute  an  adaptation 
of  wonderful  perfection,  for,  as  Sherrington  has  shown,  the 
adaptation  of  locomotion  consists  of  a  series  of  reflexes — 
ceptors  in  the  joints,  in  the  limb,  and  in  the  foot  being  stim- 
ulated by  variations  in  pressure. 

As  we  have  shown,  the  bene-  and  nociceptors  orientate 
man  to  all  forms  of  physical  contact — the  former  guide  him  to 
the  acquisition  of  food  and  to  sexual  contact;  the  latter 
direct  him  from  contacts  of  a  harmful  nature.  The  distance 
ceptors,  on  the  other  hand,  adapt  man  to  his  distant  environ- 
ment by  means  of  communication  through  unseen  forces — 
ethereal  vibrations  produce  sight ;  air  waves  produce  sound ; 
microscopic  particles  of  matter  produce  smell.  The  ad- 
vantage of  the  distance  ceptors  is  that  they  allow  time  for 
orientation,  and  because  of  this  great  advantage  the  majority 
of  man's  actions  are  responses  to  their  adequate  stimuli. 
As  Sherrington  has  stated,  the  greater  part  of  the  brain  has 
been  developed  by  means  of  stimuli  received  through  the 
special  senses,  especially  through  the  light  ceptors,  the  optic 
nerves. 

We  have  just  stated  that  by  means  of  the  distance  ceptors 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  133 

animals  and  man  orientate  themselves  to  their  distant  en- 
vironment. As  a  result  of  the  stimulation  of  the  special 
senses  chase  and  escape  are  effected,  fight  is  conducted,  food 
is  secured,  and  mates  are  found.  It  is  obvious,  therefore, 
that  the  distance  ceptors  are  the  primary  cause  of  continuous 
and  exhausting  expenditures  of  energy.  On  the  other  hand, 
stimuli  applied  to  contact  ceptors  lead  to  short,  quick  dis- 
charges of  nervous  energy.  The  child  puts  his  hand  in  the 
fire  and  there  is  an  immediate  and  complete  response  to  the 
injuring  contact;  he  sees  a  pot  of  jam  on  the  pantry  shelf 
and  a  long  train  of  continued  activities  are  set  in  motion, 
leading  to  the  acquisition  of  the  desired  object. 

The  contact  ceptors  do  not  at  all  promote  the  expenditure 
of  energy  in  the  chase  or  in  fight,  in  the  search  for  food  or  for 
mates.  Since  the  distance  ceptors  control  these  activities, 
one  would  expect  to  find  that  they  control  also  those  organs 
whose  function  is  the  production  of  energizing  internal 
secretions.  Over  these  organs — the  thyroid,  the  adrenals, 
the  hypophysis — the  contact  ceptors  have  no  control.  Pro- 
longed laboratory  experimentation  seems  to  prove  this 
postulate.  According  to  our  observations,  no  amount  of 
physical  trauma  inflicted  upon  animals  will  cause  hyper- 
thyroidism or  increased  adrenalin  in  the  blood,  while  fear 
and  rage  do  produce  hyperthyroidism  and  increased  ad- 
renalin (Fig.  44)  (Cannon).  This  is  a  statement  of  far- 
reaching  importance  and  is  the  key  to  an  explanation  of 
many  chronic  diseases — diseases  which  are  associated  with 
the  intense  stimulation  of  the  distance  ceptors  in  human 
relations. 

Stimuli  of  the  contact  ceptors  differ  from  stimuli  of  the 
distance  ceptors  in  still  another  important  particular.     The 


134 


THE   EMOTIONS 


C 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  135 

adequacy  of  stimuli  of  the  contact  ceptors  depends  upon 
their  number  and  intensity,  while  the  adequacy  of  the  stim- 
uli of  the  distance  ceptors  depends  upon  the  experience  of  the 
species  and  of  the  individual.  That  is,  according  to  phy- 
logeny  and  ontogeny  this  or  that  sound,  this  or  that  smell, 
this  or  that  sight,  through  association  recapitulates  the  ex- 
perience of  the  species  and  of  the  individual — awakens  the 
phylogenetic  and  ontogenetic  memory.  In  other  words, 
sights,  sounds,  and  odors  are  symbols  which  awaken  phylo- 
genetic association.  If  a  species  has  become  adapted  to 
make  a  specific  response  to  a  certain  object,  then  that  re- 
sponse will  occur  automatically  in  an  individual  of  that 
species  when  he  hears,  sees,  or  smells  that  object.  Suppose, 
for  example,  that  the  shadow  of  a  hawk  were  to  fall  simul- 
taneously on  the  eyes  of  a  bird,  a  rabbit,  a  cow,  and  a  boy. 
That  shadow  would  at  once  activate  the  rabbit  and  the  bird 
to  an  endeavor  to  escape,  each  in  a  specific  manner  according 
to  its  phylogenetic  adaptation ;  the  cow  would  be  indifferent 
and  neutral;  while  the  boy,  according  to  his  personal  ex- 
perience or  ontogeny,  might  remain  neutral,  might  watch 
the  flight  of  the  hawk  with  interest  or  might  try  to  shoot  it. 

Each  phylogenetic  and  each  ontogenetic  experience  by  an 
indirect  method  develops  its  own  mechanism  of  adaptation 
in  the  brain;  and  the  brain  threshold  is  raised  or  lowered  to 
stimuli  by  the  strength  and  frequency  of  repetition  of  the 
experience.  Thus  through  the  innumerable  symbols  supplied 
by  environment  the  distance  ceptors  drive  this  or  that  animal 
according  to  the  type  of  brain  pattern  and  the  particular 
state  of  threshold  which  has  been  developed  in  that  animal 
by  its  phylogenetic  and  ontogenetic  experiences.  The  brain 
pattern  depends  upon  his  phylogeny,  the  state  of  threshold 


136  THE    EMOTIONS 

upon  his  ontogeny.  Each  hrain  pattern  is  created  by  some 
particular  element  in  the  environment  to  which  an  adapta- 
tion has  been  made  for  the  good  of  the  species.  The  state 
of  threshold  depends  upon  the  effect  made  upon  the  individual 
by  his  personal  contacts  with  that  particular  element  in  his 
environment.  The  presence  of  that  element  produces  in 
the  individual  an  associative  recall  of  the  adaptation  of  his 
species — that  is,  the  brain  pattern  developed  by  his  phylo- 
geny  becomes  energized  to  make  a  specific  response.  The 
intensity  of  the  response  depends  upon  the  state  of  threshold 
— that  is,  upon  the  associative  recall  of  the  individual's  own 
experience — his  ontogeny. 

If  the  full  history  of  the  species  and  of  the  individual  could 
be  known  in  every  detail,  then  every  detail  of  that  individ- 
ual's conduct  in  health  and  disease  could  be  predicted. 
Reaction  to  environment  is  the  basis  of  conduct,  of  moral 
standards,  of  manners  and  conventions,  of  work  and  play, 
of  love  and  hate,  of  protection  and  murder,  of  governing  and 
being  governed,  in  fact,  of  all  the  reactions  between  human 
beings — of  the  entire  web  of  life.  To  quote  Sherrington 
once  more:  "Environment  drives  the  brain,  the  brain  drives 
the  various  organs  of  the  body." 

By  what  means  are  these  adaptations  made?  What  is  the 
mechanism  through  which  adequate  responses  are  made  to 
the  stimuli  received  by  the  ceptors?  We  postulate  that  in 
the  brain  there  are  innumerable  patterns  each  the  mechanism 
for  the  performance  of  a  single  kind  of  action,  and  that  the 
brain-cells  supply  the  energy — electric  or  otherwise — by 
which  the  act  is  performed;  that  the  energy  stored  in  the 
brain-cells  is  in  some  unknown  manner  released  by  the  force 
which  activates  the  brain  pattern ;   and  that  through  an  un- 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  137 

known  property  of  these  brain  patterns  each  stimulus  causes 
such  a  change  that  the  next  stimulus  of  the  same  kind  passes 
with  greater  facility. 

Each  separate  motor  action  presumably  has  its  own 
mechanism — brain  pattern — which  is  activated  by  but  one 
ceptor  and  by  that  ceptor  only  when  physical  force  of  a 
certain  intensity  and  rate  of  motion  is  applied.  This  is  true 
both  of  the  visible  contacts  affecting  the  nociceptors  and  of 
the  invisible  contacts  by  those  intangible  forces  which  affect 
the  distance  ceptors.  For  example,  each  variation  in  speed 
of  the  light-producing  waves  of  ether  causes  a  specific  reac- 
tion in  the  brain.  For  one  speed  of  ether  waves  the  reaction 
is  the  perception  of  the  color  blue;  for  another,  yellow;  for 
another,  violet.  Changes  in  the  speed  of  air  waves  meet 
with  specific  response  in  the  brain  patterns  tuned  to  receive 
impressions  through  the  aural  nerves,  and  so  we  distinguish 
differences  in  sound  pitch.  If  we  can  realize  the  infinite 
delicacy  of  the  mechanisms  adapted  to  these  infinitesimal 
variations  in  the  speed  and  intensity  of  invisible  and  in- 
tangible stimuli,  it  will  not  be  difficult  to  conceive  the  varia- 
tions of  brain  patterns  which  render  possible  the  specific 
responses  to  the  coarser  contacts  of  visible  environment. 

Each  brain  pattern  is  adapted  for  but  one  type  of  motion, 
and  so  the  specific  stimuli  of  the  innumerable  ceptors  play 
each  upon  its  own  brain  pattern  only.  In  addition,  each 
brain  pattern  can  react  to  stimuli  applied  only  within  certain 
limits.  Too  bright  a  light  blinds ;  too  loud  a  sound  deafens. 
No  mechanism  is  adapted  for  waves  of  light  above  or  below 
a  certain  rate  of  speed,  although  this  range  varies  in  different 
individuals  and  in  different  species  according  to  the  training 
of  the  individual  and  the  need  of  the  species. 


138  THE    EMOTIONS 

We  have  already  referred  to  the  fact  that  there  is  no  re- 
ceptive mechanism  adapted  to  the  stimuh  from  the  x-ray, 
from  the  high-speed  bullet,  from  electricity.  So,  too,  there 
are  innumerable  forces  in  nature  which  can  excite  in  man  no 
adaptive  response,  since  there  exist  in  man  no  brain  patterns 
tuned  to  their  waves,  as  in  the  case  of  certain  ethereal  and 
radioactive  forces. 

On  this  mechanistic  basis  the  emotions  may  be  explained 
as  activations  of  the  entire  motor  mechanism  for  fighting,  for 
escaping,  for  copulating.  The  sight  of  an  enemy  stimulates 
in  the  brain  those  patterns  formed  by  the  previous  experi- 
ences of  the  individual  with  that  enemy,  and  also  the  ex- 
periences of  the  race  whenever  an  enemy  had  to  be  met  and 
overcome.  Each  of  these  many  brain  patterns  in  turn  acti- 
vates that  part  of  the  body  through  which  lies  the  path  of  its 
own  adaptive  response — those  parts  including  the  special  en- 
ergizing or  activating  organs.  Laboratory  experiments  show 
that  in  an  animal  driven  strongly  by  emotion  the  following 
changes  maybe  seen:  (1)  A  mobilization  of  the  energy- 
giving  compound  in  the  brain-cells,  evidenced  by  a  primary 
increase  of  the  Nissl  substance  and  a  later  disappearance  of 
this  substance  and  the  deterioration  of  the  cells  (Figs.  5  and 
13);  (2)  increased  output  of  adrenalin  (Cannon),  of  thyroid 
secretion,  of  glycogen,  and  an  increase  of  the  power  of  oxida- 
tion in  the  muscles;  (3)  accelerated  circulation  and  respira- 
tion with  increased  body  temperature;  (4)  altered  metab- 
olism. All  these  are  adaptations  to  increase  the  motor 
efficiency  of  the  mechanism.  In  addition,  we  find  an  inhibi- 
tion of  the  functions  of  every  organ  and  tissue  that  consumes 
energy,  but  does  not  contribute  directly  to  motor  efficiency. 
The  mouth  becomes  dry;   the  gastric  and  pancreatic  secre- 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  139 

tions  are  lessened  or  are  completely  inhibited;  peristaltic 
action  stops.  The  obvious  purpose  of  all  these  activations 
and  inhibitions  is  to  mass  every  atom  of  energy  upon  the 
muscles  that  are  conducting  the  defense  or  attack. 

So  strong  is  the  influence  of  phylogenetic  experience  that 
though  an  enemy  to-day  may  not  be  met  by  actual  physical 
attack,  yet  the  decks  are  cleared  for  action,  as  it  were,  and 
the  weapons  made  ready,  the  body  as  a  result  being  shaken 
and  exhausted.  The  type  of  emotion  is  plainly  declared  by 
the  activation  of  the  muscles  which  would  be  used  if  the 
appropriate  physical  action  were  consummated.  In  anger 
the  teeth  are  set,  the  fists  are  clenched,  the  posture  is 
rigid;  in  fear  the  muscles  collapse,  the  joints  tremble,  and 
the  running  mechanism  is  activated  for  flight;  in  sexual 
excitement  the  mimicry  is  as  obvious.  The  emotions,  then, 
are  the  preparations  for  phylogenetic  activities.  If  the 
activities  are  consummated,  the  fuel — glycogen — and  the 
activating  secretions  from  the  thyroid,  the  adrenals,  the 
hypophysis  are  consumed.  In  the  activation  without  action, 
these  products  must  be  eUminated  as  waste  products  and  so 
a  heavy  strain  is  put  upon  the  organs  of  ehmination.  It  is 
obvious  that  the  body  under  emotion  might  be  clarified  by 
active  muscular  exercise,  but  the  subject  of  the  emotion  is 
so  strongly  integrated  thereby  that  it  is  difficult  for  him  to 
engage  in  diverting,  clarifying  exertion.  The  person  in 
anger  does  not  want  to  be  saved  from  the  ill  effects  of  his 
own  emotion;  he  wants  only  to  fight;  the  person  in  fear 
wants  only  to  escape;  the  person  under  sexual  excitement 
wants  only  possession. 

All  the  lesser  emotions — worry,  jealousy,  envy,,  grief, 
disappointment,  expectation — all  these  influence  the  body 


140  THE    EMOTIONS 

in  this  manner,  the  consequences  depending  upon  the  in- 
tensity of  the  emotion  and  its  protraction.  Chronic  emo- 
tional stimulation,  therefore,  may  fatigue  or  exhaust  the 
brain  and  may  cause  cardiovascular  disease,  indigestion, 
Graves'  disease,  diabetes,  and  insanity  even. 

The  effect  of  the  emotions  upon  the  body  mechanism  may 
be  compared  to  that  produced  upon  the  mechanism  of  an 
automobile  if  its  engines  are  kept  running  at  full  speed  while 
the  machine  is  stationary.  The  whole  machine  will  be 
shaken  and  weakened,  the  batteries  and  weakest  parts 
being  the  first  to  become  impaired  and  destroyed,  the  length 
of  usefulness  of  the  automobile  being  correspondingly 
limited. 

We  have  shown  that  the  effects  upon  the  body  mechanism 
of  the  action  of  the  various  ceptors  is  in  relation  to  the  re- 
sponse made  by  the  brain  to  the  stimuli  received.  What  is 
this  power  of  response  on  the  part  of  the  brain  but  con- 
sciousness? If  this  is  so,  then  consciousness  itself  is  a  reac- 
tion to  environment,  and  its  intensity  must  vary  with  the 
state  of  the  brain  and  with  the  environmental  stimuli.  If 
the  brain-cells  are  in  the  state  of  highest  efficiency,  if  their 
energy  has  not  been  drawn  upon,  then  consciousness  is  at 
its  height;  if  the  brain  is  fatigued,  that  is,  if  the  energy 
stored  in  the  cells  has  been  exhausted  to  any  degree,  then 
the  intensity  of  consciousness  is  diminished.  So  degrees  of 
consciousness  vary  from  the  height  maintained  by  cells  in 
full  vigor  through  the  stages  of  fatigue  to  sleep,  to  the  deeper 
unconsciousness  secured  by  the  administration  of  inhalation 
anesthetics,  to  that  complete  unconsciousness  of  the  en- 
vironment which  is  secured  by  blocking  the  advent  to  the 
brain  of  all  impressions  from  both   distance  and  contact 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  141 

ceptors,  by  the  use  of  both  local  and  inhalation  anesthetics 
— the  state  of  anoci-association  (Fig.  14). 

Animals  and  man  may  be  so  exhausted  as  to  be  only  semi- 
conscious. While  a  brain  perfectly  refreshed  by  a  long  sleep 
cannot  immediately  sleep  again,  the  exhausted  brain  and 
the  refreshed  brain  when  subjected  to  equal  stimuli  will  rise 
to  unequal  heights  of  consciousness.  The  nature  of  the 
physical  basis  of  consciousness  has  been  sought  in  experi- 
ments on  rabbits  which  were  kept  awake  from  one  hundred 
to  one  hundred  and  nine  hours.  At  the  end  of  this  time 
they  were  in  a  state  of  extreme  exhaustion  and  seemed  semi- 
conscious. If  the  wakefulness  had  been  further  prolonged, 
this  state  of  semi-consciousness  would  have  steadily  changed 
until  it  culminated  in  the  permanent  unconsciousness  of 
death.  An  examination  of  the  brain-cells  of  these  animals 
showed  physical  changes  identical  with  those  produced  by 
exhaustion  from  other  causes,  such  as  prolonged  physical 
exertion  or  emotional  strain  (Figs.  45  and  46).  After  one 
hundred  hours  of  wakefulness  the  rabbits  were  allowed  a 
long  period  of  sleep.  All  the  brain-cells  were  restored  except 
those  that  had  been  in  a  state  of  complete  exhaustion.  A 
single  seance  of  sleep  served  to  restore  some  of  the  cells, 
but  those  which  had  undergone  extreme  changes  required 
prolonged  rest.  These  experiments  give  us  a  definite  physi- 
cal basis  for  explaining  the  cost  to  the  body  mechanism 
of  maintaining  the  conscious  state.  We  have  stated  that  the 
brain-cell  changes  produced  by  prolonged  consciousness  are 
identical  with  those  produced  by  physical  exertion  and  by 
emotional  strain.  Rest,  then,  and  especially  sleep,  is  needed 
to  restore  the  physical  state  of  the  bran-cells  which  have 
been  impaired,  and  as  the  brain-cells  constitute  the  central 


142 


THE    EMOTIONS 


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144  THE    EMOTIONS 

battery  of  the  body  mechanism,  their  restoration  is  essential 
for  the  maintenance  of  normal  vitality. 

In  ordinary  parlance,  by  consciousness  we  mean  the 
activity  of  that  part  of  the  brain  in  which  associative  memory 
resides,  but  while  associative  memory  is  suspended  the 
activities  of  the  brain  as  a  whole  are  by  no  means  suspended ; 
the  respiratory  and  circulatory  centers  are  active,  as  are 
those  centers  which  maintain  muscular  tone.  This  is  shown 
by  the  muscular  response  to  external  stimuli  made  by  the 
normal  person  in  sleep;  by  the  occasional  activation  of 
motor  patterns  which  may  break  through  into  consciousness 
causing  dreams;  and  finally  by  the  responses  of  the  motor 
mechanism  made  to  the  injuring  stimuli  of  an  operation  on 
a  patient  under  inhalation  anesthesia  only. 

Direct  proof  of  the  mechanistic  action  of  many  of  life's 
phenomena  is  lacking,  but  the  proof  is  definite  and  final  of 
the  part  that  the  brain-cells  play  in  maintain  ng  conscious- 
ness ;  of  the  fact  that  the  degree  of  consciousness  and  mental 
efficiency  depends  upon  the  physical  state  of  the  brain-cells; 
and  finally  that  efficiency  may  be  restored  by  sleep,  provided 
that  exhaustion  of  the  cells  has  not  progressed  too  far.  In 
this  greatest  phenomenon  of  life,  then,  the  mechanistic 
theory  is  in  harmony  with  the  facts. 

Perhaps  no  more  convincing  proof  of  our  thesis  that  the 
body  is  a  mechanism  developed  and  adapted  to  its  purposes 
by  environment  can  be  secured  than  by  a  study  of  that  most 
constant  manifestation  of  consciousness — pain. 

Like  the  other  phenomena  of  life,  pain  was  undoubtedly 
evolved  for  a  particular  purpose — surely  for  the  good  of  the 
individual.  Like  fear  and  worry,  it  frequently  is  injurious. 
What  then  may  be  its  purpose? 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  145 

We  postulate  that  pain  is  a  result  of  contact  ceptor  stimu- 
lation for  the  purpose  of  securing  protective  muscular  ac- 
tivity. This  postulate  applies  to  all  kinds  of  pain,  whatever 
their  cause — whether  physical  injury,  pyogenic  infection, 
the  obstruction  of  hollow  viscera,  childbirth,  etc. 

All  forms  of  pain  are  associated  with  muscular  action,  and 
as  in  every  other  stimulation  of  the  ceptors,  each  kind  of  pain 
is  specific  to  the  causative  stimuli.  The  child  puts  his  hand 
in  the  fire;  physical  injury  pain  results,  and  the  appropriate 
muscular  response  is  elicited.  If  pressure  is  prolonged  on 
some  parts  of  the  body,  anemia  of  the  parts  may  result,  with 
a  corresponding  discomfort  or  pain,  requiring  muscular 
action  for  relief.  When  the  rays  of  the  sun  strike  directly 
upon  the  retina,  light  pain  causes  an  immediate  protective 
action;  so  too  in  the  evacuation  of  the  intestine  and  the 
urinary  bladder  as  normal  acts,  and  in  overcoming  obstruc- 
tion of  these  tracts,  discomfort  or  pain  compel  the  required 
muscular  actions.  This  view  of  pain  as  a  stimulation  to 
motor  action  explains  why  only  certain  types  of  infection  are 
associated  with  pain;  namely,  those  types  in  which  the 
infection  may  be  spread  by  muscular  action  or  those  in  which 
the  fixation  of  parts  by  continued  muscular  rigidity  is  an  ad- 
vantage. As  a  further  remarkable  proof  of  the  marvelous 
adaptation  of  the  body  mechanism  to  meet  varying  environ- 
mental conditions,  we  find  that  just  as  nociceptors  have  been 
implanted  in  only  those  parts  of  the  body  which  have  been 
subject  to  nocuous  contacts,  so  a  type  of  infection  which 
causes  muscular  action  in  one  part  of  the  body  may  cause 
none  when  it  attacks  another. 

This  postulate  gives  us  the  key  to  the  pain-muscular 
phenomena  of  peritonitis,   pleurisy,   cystitis,   cholecystitis, 

10 


146  THE    EMOTIONS 

etc.,  as  well  as  to  the  pain-muscular  phenomena  in  obstruc- 
tions of  the  hollow  viscera.  If  pain  is  a  part  of  a  muscular 
response  and  occurs  only  as  a  result  of  contact  ceptor  stimu- 
lation by  physical  injury,  infection,  anemia,  or  obstruction, 
we  may  well  inquire  which  part  of  the  nerve  mechanism  is 
the  site  of  the  phenomenon  of  pain.  Is  it  the  nerve-ending, 
the  nerve-trunk,  or  the  brain?  That  is,  is  pain  associated 
with  the  physical  contact  with  the  nerve-ending,  or  with  the 
physical  act  of  transmission  along  the  nerve-trunk,  or  with 
the  change  of  brain-cell  substance  by  means  of  which  the 
motor-producing  energy  is  released? 

We  postulate  that  the  pain  is  associated  with  the  dis- 
charge of  energy  from  the  brain-cells.  If  this  be  true,  then 
if  every  nociceptor  in  the  body  were  equally  stimulated  in 
such  a  manner  that  all  the  stimuli  should  reach  the  brain- 
cells  simultaneously,  then  the  cells  would  find  themselves  in 
equilibrium  and  no  motor  act  would  be  performed.  But  if 
all  the  pain  nerve  ceptors  but  one  were  equally  stimulated, 
and  this  one  more  strongly  stimulated  than  the  rest,  then 
this  one  would  gain  possession  of  the  final  common  path — 
would  cause  a  muscular  action  and  the  sensation  of  pain. 

It  is  well  known  that  when  a  greater  pain  or  stimulus  is 
thrown  into  competition  with  a  lesser  one,  the  lesser  is  sub- 
merged. Of  this  fact  the  school-boy  makes  use  when  he 
initiates  the  novice  into  the  mystery  of  the  painless  pulling 
of  hair.  The  simultaneous  but  severe  application  of  the 
boot  to  the  blindfolded  victim  takes  complete  but  exclusive 
possession  of  the  final  common  path  and  the  hair  is  pain- 
lessly plucked  as  a  result  of  the  triumph  of  the  boot  stimulus 
over  the  pull  on  the  hair  in  the  struggle  for  the  final  common 
path. 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  147 

Persons  who  have  survived  a  sudden,  complete  exposure 
to  superheated  steam,  or  whose  bodies  have  been  enwrapped 
in  flame,  testify  that  they  have  felt  no  pain.  As  this  absence 
of  pain  may  be  due  to  the  fact  that  the  emotion  of  fear 
gained  the  final  common  path,  to  the  exclusion  of  all  other 
stimuli,  we  are  trying  by  experimentation  to  discover  the 
effects  of  simultaneous  painful  stimulation  of  all  parts  of  the 
body.  The  data  already  in  hand,  and  the  experiments  now 
in  progress,  in  which  anesthetized  animals  are  subjected  to 
powerful  stimuli  applied  to  certain  parts  of  the  body  only, 
or  simultaneously  to  all  parts  of  the  body,  lead  us  to  believe 
that  in  the  former  case  the  brain-cells  become  stimulated  or 
hyperchromatic,  while  in  the  latter  case  no  brain-cell  changes 
occur.  We  believe  that  our  experiments  will  prove  that  an 
equal  and  simultaneous  stimulation  of  all  parts  of  the  body 
leaves  the  brain-cells  in  a  state  of  equilibrium.  Our  theory 
of  pain  will  then  be  well  sustained,  not  only  by  common 
observation,  but  by  experimental  proof,  and  so  the  mechanis- 
tic view  will  be  found  in  complete  harmony  with  another 
important  reaction. 

We  have  stated  that  when  a  number  of  contact  stimuli  act 
simultaneously,  the  strongest  stimulus  will  gain  possession  of 
the  final  common  path — the  path  of  action.  When,  how- 
ever, stimuli  of  the  distance  ceptors  compete  with  stimuli  of 
the  contact  ceptors,  the  contact-ceptor  stimuli  often  secure 
the  common  path,  not  because  they  are  stronger  or  more 
important,  but  because  they  are  immediate  and  urgent.  In 
many  instances,  however,  the  distance-ceptor  stimuli  are 
strong,  have  the  advantage  of  a  lowered  threshold,  and 
therefore  compete  successfully  with  the  immediate  and 
present  stimuli  of  the  contact  ceptors.     In  such  cases  we 


148  THE    EMOTIONS 

have  the  interesting  phenomenon  of  physical  injury  without 
resultant  pain  or  muscular  response.  The  distance-ceptor 
stimuli  which  may  thus  triumph  over  even  powerful  contact- 
ceptor  stimuli  are  those  causing  strong  emotions — as  great 
anger  in  fighting;  great  fear  in  a  battle;  intense  sexual 
excitement.  Dr.  Livingstone  has  testified  to  his  complete 
unconsciousness  to  pain  during  his  struggle  with  a  lion; 
although  he  was  torn  by  teeth  and  claws,  his  fear  overcame 
all  other  impressions.  By  frequently  repeated  stimulation 
the  Dervish  secures  a  low  threshold  to  the  emotions  caused 
by  the  thought  of  God  or  the  devil,  and  his  emotional  excite- 
ment is  increased  by  the  presence  of  others  under  the  same 
stimulation;  emotion,  therefore,  secures  the  final  conunon 
path  and  he  is  unconscious  of  pain  when  he  lashes,  cuts,  and 
bruises  his  body.  The  phenomena  of  hysteria  may  be  ex- 
plained on  this  basis,  as  may  the  unconsciousness  of  passing 
events  in  a  person  in  the  midst  of  a  great  and  overwhelming 
grief.  By  constant  practice  the  student  may  secure  the 
final  common  path  for  such  impressions  as  are  derived  from 
the  stimuli  offered  by  the  subject  of  his  study,  and  so  he  will 
be  oblivious  of  his  surroundings.  Concentration  is  but 
another  name  for  a  final  common  path  secured  by  the  repe- 
tition and  summation  of  certain  stimuli. 

If  our  premises  are  sustained,  then  we  can  recognize  in  man 
no  will,  no  ego,  no  possibility  for  spontaneous  action,  for 
every  action  must  be  a  response  to  the  stimuli  of  contact  or 
distance  ceptors,  or  to  their  recall  through  associative 
memory.  Memory  is  awakened  by  symbols  which  represent 
any  of  the  objects  or  forces  associated  with  the  act  recalled. 
Spoken  and  written  words,  pictures,  sounds,  may  stimulate 
the  brain  patterns  formed  by  previous  stimulation  of  the 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  149 

distance  ceptors;  while  touch,  pain,  temperature,  pressure, 
may  recall  previous  contact-ceptor  stimuli.  Memory  de- 
pends in  part  upon  the  adequacy  of  the  symbol,  and  in  part 
upon  the  state  of  the  threshold.  If  one  has  ever  been  at- 
tacked by  a  snake,  the  threshold  to  any  symbol  which  could 
recall  that  attack  would  be  low ;  the  later  recall  of  anything 
associated  with  the  bite  or  its  results  would  produce  in  mem- 
ory a  recapitulation  of  the  whole  scene,  while  even  harmless 
snakes  would  thereafter  be  greeted  with  a  shudder.  On  the 
other  hand,  in  a  child  the  threshold  is  low  to  the  desire  for 
the  possession  of  any  new  and  strange  object;  in  a  child, 
therefore,  to  whom  a  snake  is  merely  an  unusual  and  fascinat- 
ing object,  there  is  aroused  only  curiosity  and  the  desire  for 
the  possession  of  a  new  plaything. 

If  we  are  to  attribute  to  man  the  possession  of  a  governing 
attribute  not  possessed  by  other  parts  of  the  animal  creation, 
where  are  we  to  draw  the  boundary  line,  and  say  "here  the 
ego — the  will — the  reason — emerges ' '  ?  What  attribute,  after 
all,  has  man  which  in  its  ultimate  analysis  is  not  possessed 
by  the  lowest  animals  or  by  the  vegetable  creation,  even? 
From  the  ameba,  on  through  all  the  stages  of  animal  exist- 
ence, every  action  is  but  a  response  to  an  adequate  stimulus ; 
and  as  a  result  of  adequate  stimuli  each  step  has  been  taken 
toward  the  higher  and  more  intricate  mechanisms  which  play 
the  higher  and  more  intricate  parts  in  the  great  scheme  of 
nature. 

The  Venus  fly-trap  responds  to  as  delicate  a  stimulus  as  do 
any  of  the  contact  ceptors  of  animals,  and  the  motor  activity 
resulting  from  the  stimulus  is  as  complex.  To  an  insect-like 
touch  the  plant  responds;  to  a  rough  contact  there  is  no 
response;    that  is,  the  motor  mechanism  of  the  plant  has 


150  THE    EMOTIONS 

become  attuned  to  only  such  stimuli  as  simulate  the  contact 
of  those  insects  which  form  its  diet.  It  catches  flies,  eats 
and  digests  them,  and  ejects  the  refuse  (Fig.  47).  The 
ameba  does  no  less.  The  frog  does  no  more,  excepting  that 
in  its  place  in  creation  a  few  more  reactions  are  required  for 
its  sustenance  and  for  the  propagation  of  its  species.  Man 
does  no  more,  excepting  that  in  man's  manifold  relations 
there  are  innumerable  stimuli,  for  meeting  which  adequately, 
innumerable  mechanisms  have  been  evolved.  The  motor 
mechanism  of  the  fly-trap  is  perfectly  adapted  to  its  purpose. 
The  motor  mechanism  of  man  is  adapted  to  its  manifold  uses, 
and  as  new  environmental  influences  surround  him,  we  must 
believe  that  new  adaptations  of  the  mechanism  will  be 
evolved  to  meet  the  new  conditions. 

Is  not  this  conception  of  man's  activities  infinitely  more 
wonderful,  and  infinitely  more  comprehensible  than  is  the 
conception  that  his  activities  may  be  accounted  for  by  the 
existence  of  an  unknown,  unimaginable,  and  intangible  force 
called ''mind"  or ''soul"? 

We  have  already  shown  how  the  nerve  mechanism  is  so 
well  adapted  to  the  innumerable  stimuli  of  environment  that 
it  can  accurately  transmit  and  distinguish  between  the 
infinite  variations  of  speed  in  the  ether  waves  producing 
light,  and  the  air  waves  producing  sound.  Each  rate  of 
vibration  energizes  only  the  mechanism  which  has  been 
attuned  to  it.  With  marvelous  accuracy  the  light  and  sound 
waves  gain  access  to  the  nerve  tissue  and  are  finally  inter- 
preted in  terms  of  motor  responses,  each  by  the  brain  pattern 
attuned  to  that  particular  speed  and  intensity.  So  stimuh 
and  resultant  actions  multiplied  by  the  tota^  number  of  the 


A   MECHANISTIC    VIEW   OF    PSYCHOLOGY 


151 


Fig.  47. — Venus'  Fly-trap — Diancca  muscipula  (Linnseus). 
When  an  insect  alights  upon  a  leaf,  the  leaf  closes  upon  it  like  a  spring  trap 
in  a  few  seconds  and  digests  the  insect,  taking,  perhaps,  a  fortnight  over  a 
meal.     Detail — lateral  view  of  expanded  leaf. 


152  THE    EMOTIONS 

motor  patterns  in  the  brain  of  man  give  us  the  sum  total  of 
his  hfe's  activities — they  constitute  his  hfe. 

As  in  evolutionary  history  the  permanence  of  an  adapta- 
tion of  the  body  mechanism  depends  upon  its  value  in  the 
preservation  of  the  life  of  the  individual  and  upon  its  power 
to  increase  the  value  of  the  individual  to  the  race,  so  the 
importance  and  truth  of  these  postulates  and  theories  may 
well  be  judged  on  the  same  basis. 

The  fundamental  instincts  of  all  living  matter  are  self- 
preservation  and  the  propagation  of  the  species.  The  in- 
stinct for  self-preservation  causes  a  plant  to  turn  away  from 
cold  and  damaging  winds  toward  the  life-giving  sun;  the 
inert  mussel  to  withdraw  within  its  shell;  the  insect  to  take 
flight;  the  animal  to  fight  or  to  flee;  and  man  to  procure 
food  that  he  may  oppose  starvation,  to  shelter  himself  and 
to  provide  clothes  that  he  may  avoid  the  dangers  of  excessive 
cold  and  heat,  to  combat  death  from  disease  by  seeking 
medical  aid,  to  avoid  destruction  by  man  or  brute  by  fight 
or  by  flight.  The  instinct  to  propagate  the  species  leads 
brute  man  by  crude  methods,  and  cultured  man  by  methods 
more  refined,  to  put  out  of  his  way  sex  rivals  so  that  his  own 
life  may  be  continued  through  offspring.  The  life  of  the 
species  is  further  assured  by  the  protective  action  exercised 
over  the  young  by  the  adults  of  the  species.  As  soon  as  the 
youngest  offspring  is  able  successfully  to  carry  on  his  own 
struggle  with  environment  there  is  no  longer  need  for  the 
parent,  and  the  parent  enters  therefore  the  stage  of  disinte- 
gration. The  average  length  of  life  in  any  species  is  the  sum 
of  the  years  of  immaturity,  plus  the  years  of  female  fertility, 
plus  the  adolescent  years  of  the  offspring. 

The  stimuli  resulting  from  these  two  dominant  instincts 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  153 

are  now  so  overpowering  as  compared  with  all  other  environ- 
mental stimuli  that  the  mere  possession  of  adequate  knowl- 
edge of  the  damaging  effects  of  certain  actions  as  compared 
with  the  saving  effects  of  others  will  (other  things  being 
equal)  lead  the  individual  to  choose  the  right, — the  self-  and 
species-preservative  course  of  action,  instead  of  the  wrong, — 
the  self-  and  species-destructive  course  of  action. 

The  dissemination  of  the  knowledge  of  the  far-reaching 
deleterious  effects  of  protracted  emotional  strain,  of  over- 
work, and  of  worry  will  automatically  raise  man's  threshold 
to  the  damaging  activating  stimuli  causing  the  strong  emo- 
tions, and  will  cause  him  to  avoid  dangerous  strains  of  every 
kind.  The  individual  thus  protected  will  therefore  rise  to  a 
plane  of  poise  and  efficiency  far  above  that  of  his  uncon- 
trolled fellows,  and  by  so  much  will  his  efficiency,  health,  and 
happiness  be  augmented. 

A  full  acceptance  of  this  theory  cannot  fail  to  produce  in 
those  in  whose  charge  rests  the  welfare  of  the  young,  an  over- 
whelming desire  to  surround  children  with  those  environ- 
mental stimuli  only  which  will  tend  to  their  highest  ultimate 
welfare. 

Such  is  the  stimulating  force  of  tradition  that  many  who 
have  been  educated  under  the  tenets  of  traditional  beliefs 
will  oppose  these  hypotheses — even  violently,  it  may  be. 
So  they  have  opposed  them;  so  they  opposed  Darwin;  so 
they  have  opposed  all  new  and  apparently  revolutionary 
doctrines.  Yet  these  persons  themselves  are  by  their  very 
actions  proving  the  efficiency  of  the  vital  principles  which 
we  have  enunciated.  What  is  the  whole  social  welfare 
movement  but  a  recognition  on  the  part  of  municipalities, 
educational  boards,  and  religious  organizations  of  the  fact 


154  THE    EMOTIONS 

that  the  future  welfare  of  the  race  depends  upon  the  ad- 
ministration to  the  young  of  forceful  uplifting  environmental 
stimuli? 

There  are  now,  as  there  were  in  Darwin's  day,  many  who 
feel  that  man  is  degraded  from  his  high  estate  by  the  con- 
ception that  he  is  not  a  reasoning,  willing  being,  the  result  of 
a  special  creation.  But  one  may  wonder  indeed  what  con- 
ception of  the  origin  of  man  can  be  more  wonderful  or  more 
inspiring  than  the  belief  that  he  has  been  slowly  evolved 
through  the  ages,  and  that  all  creatures  have  had  a  part  in 
his  development ;  that  each  form  of  life  has  contributed  and 
is  contributing  still  to  his  present  welfare  and  to  his  future 
advancement. 

Recapitulation 

Psychology, — the  science  of  the  human  soul  and  its  rela- 
tions,— under  the  mechanistic  theory  of  life,  must  receive  a 
new  definition.  It  becomes  a  science  of  man's  activities  as 
determined  by  the  environmental  stimuli  of  his  phylogeny 
and  of  his  ontogeny. 

On  this  basis  we  postulate  that  throughout  the  history  of 
the  race  nothing  has  been  lost,  but  that  every  experience  of 
the  race  and  of  the  individual  has  been  retained  for  the 
guidance  of  the  individual  and  of  the  race;  that  for  the 
accomplishment  of  this  end  there  has  been  evolved  through 
the  ages  a  nerve  mechanism  of  such  infinite  delicacy  and 
precision  that  in  some  unknown  manner  it  can  register  per- 
manently within  itself  every  impression  received  in  the 
phylogenetic  and  ontogenetic  experience  of  the  individual; 
that  each  of  these  nerve  mechanisms  or  brain  patterns  has  its 
own  connection  with  the  external  world,  and  that  each  is 


A    MECHANISTIC    VIEW    OF    PSYCHOLOGY  155 

attuned  to  receive  impressions  of  but  one  kind,  as  in  the 
apparatus  of  wireless  telegraphy  each  instrument  can  receive 
and  interpret  waves  of  a  certain  rate  of  intensity  only;  that 
thought,  will,  ego,  personality,  perception,  imagination, 
reason,  emotion,  choice,  memory,  are  to  be  interpreted  in 
terms  of  these  brain  patterns;  that  these  so-called  phe- 
nomena of  human  life  depend  upon  the  stimuli  which  can 
secure  the  final  common  path,  this  in  turn  having  been  de- 
termined by  the  frequency  and  the  strength  of  the  environ- 
mental stimuli  of  the  past  and  of  the  present. 

Finally,  as  for  life's  origin  and  life's  ultimate  end,  we  are 
content  to  say  that  they  are  unknown,  perhaps  unknowable. 
We  know  only  that  living  matter,  like  lifeless  matter,  has 
its  own  place  in  the  cosmic  processes;  that  the  gigantic 
forces  which  operated  to  produce  a  world  upon  which  life 
could  exist,  as  a  logical  sequence,  when  the  time  was  ripe, 
evolved  life;  and  finally  that  these  cosmic  forces  are  still 
active,  though  none  can  tell  what  worlds  and  what  races  may 
be  the  result  of  their  coming  activities. 


A  MECHANISTIC  THEORY  OF  DISEASE* 

The  human  body  is  an  elaborate  mechanism  equipped 
first  for  such  conflict  with  environment  as  will  tend  to  the 
preservation  of  the  individual,  and  second  for  the  propaga- 
tion of  the  species,  both  of  these  functions,  when  most 
efficiently  carried  out,  tending  to  the  upbuilding  and  per- 
fection of  the  race.  From  the  date  of  Harvey's  discovery  of 
the  circulation  of  the  blood,  to  the  present  day,  the  human 
body  has  been  constantly  compared  to  a  machine,  but  the 
time  for  analogy  and  comparison  is  past.  I  postulate  that 
the  body  is  itself  a  mechanism  responding  in  every  part  to 
the  adequate  stimuli  given  it  from  without  by  the  environ- 
ment of  the  present  and  from  within  by  the  environment  of 
the  past,  the  memory  of  which  is  stored  in  the  central  battery 
of  the  mechanism — the  brain. 


If  the  full  history  of  the  species  and  of  the  individual  could 
be  known  in  every  detail,  then  every  detail  of  that  individual's 
conduct  in  health  and  disease  could  be  predicted.  Reaction 
to  environment  is  the  basis  of  conduct,  of  moral  standards,  of 
manners  and  conventions,  of  work  and  play,  of  love  and  hate, 

*  Oration  in  Surgery.  Delivered  at  the  147th  Annual  Meeting  of  the  Medi- 
cal Society  of  New  Jersey,  at  Spring  Lake,  N.  J.,  June  11,  1913. 

In  this  address  the  paragraphs  which  were  taken  from  the  preceding  paper, 
"A  Mechanistic  View  of  Psychology,"  have  been  omitted,  those  portions  only 
being  republished  in  which  the  premises  have  been  applied  in  a  discussion  of 
certain  medical  problems  rather  than  of  psychological  problems. 

157 


158  THE    EMOTIONS 

of  protection  and  murder,  of  governing  and  being  governed, 
in  fact,  of  all  the  reactions  between  human  beings — of  the 
entire  web  of  life.  As  Sherrington  has  stated,  ''Environ- 
ment drives  the  brain,  the  brain  drives  the  various  organs  of 
the  body, "  and  here  we  believe  we  find  the  key  to  a  mechan- 
istic interpretation  of  all  body  processes. 

On  this  basis  we  may  see  that  the  activities  of  life  depend 
upon  the  ability  of  the  parts  of  the  body  mechanism  to  re- 
spond adequately  to  adequate  stimulation.  This  postulate 
applies  not  only  to  stimuU  from  visible  forces,  but  to  those 
received  by  the  invasion  of  the  micro-bodies  which  cause 
pyogenic  or  non-pyogenic  infections.  In  the  case  of  danger- 
ous assaults  by  visible  or  invisible  enemies,  the  brain,  through 
the  nerves  and  all  parts  of  the  motor  mechanism,  meets  the 
attack  by  attempts  at  adaptation.  Recovery,  invalidism, 
and  death  depend  upon  the  degree  of  success  with  which  the 
attacking  or  invading  enemies  are  met.  Questions  regarding 
disease  become,  therefore,  questions  in  adaptation,  and  it  is 
possible  that,  when  studied  in  the  light  of  this  conception, 
the  key  to  many  hitherto  unsolved  physical  problems  may 
be  found. 

Perhaps  no  more  convincing  proof  of  our  thesis  may  be 
secured  than  by  a  study  of  that  ever-present  phenomenon — 
pain.  In  whatever  part  of  the  body  and  by  whatever 
apparent  cause  pain  is  produced,  we  find  that  it  is  invariably 
a  stimulation  to  motor  activity — whose  ultimate  object  is 
protection.  Thus  by  the  muscular  action  resulting  from 
pain  we  are  protected  against  heat  and  cold;  against  too 
powerful  light;  against  local  anemia  caused  by  prolonged 
pressure  upon  any  portion  of  the  body.  So,  too,  pain  of 
greater  or  less  intensity  compels  the  required  emptying  of 


A    MECHANISTIC    THEORY    OF    DISEASE  159 

the  pregnant  uterus  and  the  evacuation  of  the  intestine  and 
the  urinary  bladder. 

It  should  be  noted  that  in  every  instance  the  muscular 
activity  resulting  from  pain  is  specific  in  its  type,  its  dis- 
tribution, and  its  intensity,  this  specificity  being  true  not 
only  of  pain  which  is  the  result  of  external  stimulation,  but 
also  of  the  pain  associated  with  certain  types  of  infection. 


Pain,  however,  is  not  the  only  symptom  of  the  invasion  of 
the  body  by  pyogenic  or  parasitic  organisms.  Fever,  invari- 
ably, and  chills,  often,  accompany  the  course  of  the  infec- 
tions. Can  these  phenomena  also  be  explained  as  adapta- 
tions of  the  motor  mechanism  for  the  good  of  the  indi- 
vidual? 

As  the  phenomena  of  chills  and  fever  are  most  strikingly  ex- 
hibited in  malaria,  let  us  study  the  course  of  events  in  that 
disease.  It  is  known  that  the  malarial  parasite  develops  in 
the  red  blood-corpuscles,  and  that  the  chills  and  fever  appear 
when  the  cycle  of  parasitic  development  is  complete  and  the 
adults  are  ready  to  escape  from  the  corpuscles  of  the  blood 
plasma.  Bass,  of  New  Orleans,  has  proved  that  the  favor- 
able temperature  for  the  growth  of  the  malarial  organism  is 
98°,  and  that  at  102°  the  adult  organisms  will  be  killed, 
though  the  latter  temperature  is  not  fatal  to  the  spores. 
The  adult  life  of  the  malarial  parasite  begins  after  its  escape 
into  the  blood  plasma,  and  it  is  there  that  the  organism 
is  most  susceptible  to  high  temperature.  We  must  infer, 
therefore,  that  the  fever  is  an  adaptation  on  the  part  of  the 
host  for  despatching  the  enemy. 

What,  then,  may  be  the  protective  part  played  by  the 


160  THE    EMOTIONS 

chill?  A  chill  is  made  up  of  intermittent  contractions  of  all 
the  external  muscles  of  the  body.  This  activity  results  in 
an  increase  of  the  body  heat  and  in  an  anemia  of  the  super- 
ficial parts  of  the  body,  so  that  less  heat  can  be  lost  by  radia- 
tion. By  this  means,  therefore,  the  external  portions  of  the 
body  contribute  measurably  to  the  production  of  the  bene- 
ficent and  saving  fever. 

It  must  be  remembered  that  this  power  of  adaptation  is 
not  pecuhar  to  man  alone,  but  that  it  is  a  quality  shared  by 
all  hving  creatures.  While  the  human  body  has  been  adapt- 
ing itself  for  self-protection  by  producing  a  febrile  reaction 
whereby  to  kill  the  invading  organisms,  the  invaders  on  their 
side  have  been  adapting  themselves  for  a  hfe  struggle  within 
the  body  of  the  host.  In  these  mortal  conflicts  between 
invaders  and  host,  therefore,  the  issue  is  often  in  doubt,  and 
sometimes  one  and  sometimes  the  other  will  emerge  victori- 
ous. 

We  must  beheve  that  a  similar  adaptive  response  exists  in 
all  parasitic  infections — the  cycles  varying  according  to  the 
stages  in  the  development  of  the  invaders.  If  the  bacteria 
develop  continuously,  the  fever  is  constant  instead  of  inter- 
mittent, since  the  adequate  stimulus  is  constantly  present. 

Bacteriology  has  taught  us  that  both  heat  and  cold  are 
fatal  to  pathogenic  infections;  for  this  reason  either  of  the 
apparently  contradictory  methods  of  treatment  may  help, 
i.  e.,  either  hot  or  cold  applications.  It  should  be  borne  in 
mind,  however,  that  we  have  to  deal  not  only  with  the  adult 
organisms,  but  with  the  spores  also.  The  apphcation  of 
cold  may  keep  the  spores  from  developing,  while  heat  may 
promote  their  development,  and  the  course  of  the  disease 
may  vary,  therefore,  according  to  our  choice  of  treatment. 


A    MECHANISTIC    THEORY    OF    DISEASE  161 

From  this  viewpoint,  we  can  understand  the  intermittent 
temperature  in  a  patient  who  is  convalescing  from  an  ex- 
treme infection,  as  peritonitis,  pylephlebitis,  multiple  ab- 
scess of  the  hver,  etc.  In  these  conditions  there  may  occur 
days  of  normal  temperature,  followed  by  an  abrupt  rise 
which  will  last  for  several  days — this  in  turn  succeeded  by 
another  remittance.  This  cycle  may  be  repeated  several 
times,  and  on  our  hypothesis  we  may  beheve  it  is  caused  by 
the  successive  development  to  maturity  of  spores  of  varying 
ages. 

If  these  premises  are  sound,  the  wisdom  of  reducing  the 
temperature  in  case  of  infection  may  well  be  questioned. 

On  this  mechanistic  basis  the  emotions  also  may  be  ex- 
plained as  activations  of  the  entire  motor  mechanism  for 
fighting,  for  escaping,  for  copulating. 


The  emotions,  then,  are  the  preparation  for  phylogenetic 
activities  (Fig.  48).  If  the  activities  were  consummated, 
the  fuel — glycogen — and  the  activating  secretions  from  the 
thyroid,  the  adrenals,  the  hypophysis,  would  be  consumed. 
In  the  activation  without  action  these  products  must  be 
eliminated  as  waste  products  and  so  a  heavy  strain  is  put 
upon  the  organs  of  elimination.  It  is  obvious  that  the  body 
under  emotion  might  be  clarified  by  active  muscular  exercise, 
but  the  subject  of  the  emotion  is  so  strongly  integrated 
thereby  that  it  is  difficult  for  him  to  engage  in  diverting, 
clarifying  exertion. 
*********** 
*********** 

So,  as  we  have  indicated  already,  certain  deleterious  effects 
11 


162 


THE    EMOTIONS 


are  produced  when  the  body  mechanism  is  activated  without 
resultant  action.  For  example,  the  output  of  adrenahn  is 
increased,  and,  as  a  consequence,  arteriosclerosis  and  cardio- 


FiG.  48. — Violent  Effort. 
The  identity  of  the  muscular  activation  which  is  called  forth  by  extreme 
muscular  exertion  with  that  called  forth  by  intense  emotion  is  illustrated  by 
the  facial  expression  of  this  model,  sculptured  from  life  by  Dr.  R.  Tait  Mc- 
Kenzie,  of  the  University  of  Pennsylvania.  This  model  and  those  in  Fig. 
52  were  made  after  a  careful  study  of  athletes  at  the  moment  of  supreme  effort. 
(Photo  by  H.  D.  Jones,  from  Underwood  and  Underwood,  N.  Y.) 


vascular  disease  may  occur  in  persons  who  have  been  sub- 
jected to  prolonged  emotional  strain,  since  it  has  been  proved 
that  the  prolonged  administration  of  adrenalin  will  cause 
these  conditions.  We  have  stated  that  the  emotions  cause 
increased  output  of  glycogen.     Glycogen  is  a  step  toward 


A   MECHANISTIC    THEORY    OF    DISEASE  163 

diabetes,  and  therefore  this  disease,  too,  is  prone  to  appear 
in  persons  under  emotional  strain.  It  is  most  common  in 
those  races  which  are  especially  emotional  in  character,  so 
we  are  not  surprised  to  find  it  especially  prevalent  among 
Jews.  So  common  is  this  particular  result  of  prolonged 
emotion  that  some  one  has  said,  ''When  the  stocks  go  down 
in  New  York,  diabetes  goes  up."  Nephritis,  also,  may 
result  from  emotional  stress,  because  of  the  strain  put  upon 
the  kidneys  by  the  unconsumed  activating  substances.  The 
increased  heart  action  and  the  presence  of  these  activating 
secretions  may  cause  myocarditis  and  heart  degeneration. 
Claudication  also  may  result  from  the  impaired  circulation. 

The  emotions  may  cause  an  inhibition  of  the  digestive 
secretions  and  of  intestinal  peristalsis.  This  means  that 
the  digestive  processes  are  arrested,  that  putrefaction  and 
autointoxication  will  result,  and  that  still  further  strain  will 
thus  be  put  upon  the  organs  of  elimination.  Who  has  not 
observed  in  himself  and  in  others  when  under  the  influence 
of  fear,  anger,  jealousy,  or  grief  that  the  digestive  processes 
and  general  well-being  are  rapidly  and  materially  altered; 
while  as  tranquillity,  peace,  and  happiness  return  the  physi- 
cal state  improves  accordingly? 

Dentists  testify  that  as  a  result  of  continued  strong  emo- 
tion the  character  of  the  saliva  changes,  pyorrhea  develops, 
and  the  teeth  decay  rapidly.  Every  one  knows  that  strong 
emotion  may  cause  the  hair  to  fall  out  and  to  become  pre- 
maturely gray. 

As  to  the  most  important  organ  of  all — the  brain — every 
one  is  conscious  of  its  impaired  efficiency  under  emotional 
strain,  and  laboratory  researches  show  that  the  deficiency 
is  accounted  for  by  actual  cell  deterioration ;  so  the  individual 


164  THE    EMOTIONS 

who  day  by  day  is  under  heavy  emotional  strain  finds  him- 
self losing  strength  slowly — especially  do  his  friends  note  it. 
By  summation  of  stimuli  his  threshold  becomes  lowered  until 
stimuU,  which  under  normal  conditions  would  be  of  no  effect, 
produce  undue  responses.  ''The  grasshopper  becomes  a 
burden/'  and  prolonged  rest  and  change  of  environmental 
conditions  are  necessary  for  restoration. 

If  in  a  long  emotional  strain  the  brain  is  beaten  down;  if 
the  number  of  ''low-efficiency"  cells  increases,  the  driving 
powder  of  the  brain  is  correspondingly  lessened  and  therefore 
the  various  organs  of  the  body  may  escape  through  the  very 
inefficiency  of  the  brain  to  produce  in  them  forced  activity. 
On  the  other  hand,  if  the  brain  remains  vigorous,  the  kidneys 
may  take  the  strain  and  break  down;  if  the  kidneys  do  not 
break,  the  blood-vessels  may  harden;  if  the  blood-vessels 
are  not  affected,  the  thyroid  may  become  hyperplastic  and 
produce  Graves'  disease;  if  the  thyroid  escapes,  diabetes 
may  develop;  while  if  the  iron  constitution  of  the  mechan- 
ism can  successfully  bear  the  strain  in  all  its  parts,  then  the 
individual  will  break  his  competitors,  and  their  mechanisms 
will  suffer  in  the  struggle. 

This  whole  train  of  deleterious  results  of  body  activation 
without  action  may  be  best  observed  and  studied  in  that 
most  emotional  of  diseases — exophthalmic  goiter.  In  this 
disease  the  constantly  stimulated  distance  ceptors  dispossess 
the  contact  ceptors  from  the  common  path,  and  drive  the 
motor  mechanism  to  its  own  destruction,  and  the  patient 
has  the  appearance  of  a  person  in  great  terror,  or  of  a  runner 
approaching  the  end  of  a  Marathon  race  (Figs.  16  and  48  to 
54). 

Exophthalmic  goiter  may  result  from  long  emotional  or 


A   MECHANISTIC    THEOKY    OF    DISEASE 


165 


mental  stress  in  those  cases  in  which  the  thyroid  takes  the 
brunt  of  the  strain  upon  the  mechanism.  As  adrenalin 
increases  blood-pressure,  so  thyroid  secretion  increases  brain 
activity,  and  increased  brain  activity  in  turn  causes  an  in- 
creased activation  of  the  motor  mechanism  as  a  whole. 

We  know  that  a  deficiency  or  lack  of  thyroid  secretion 
will  inhibit  sexual  emotion  and  conception;    will  produce 


Fig.  49. — Runners  at  Finish  of  Four-mile  Race. 
Two  show  the  typical  facies  of  fear;   the  third,  that  of  exhaustion. 


stupidity  and  inertia;  will  diminish  vitality.  On  the  other 
hand,  excessive  thyroid  secretion  drives  the  entire  mechan- 
ism at  top  speed;  the  emotions  are  intensified;  the  skin 
becomes  soft  and  moist,  the  eyes  are  brilliant  and  staring; 
the  limbs  tremble;  the  heart  pounds  loudly  and  its  pulsa- 
tions often  are  visible ;  the  respiration  is  rapid ;  the  stimula- 
tion of  the  fear  mechanism  causes  the  eyes  to  protrude 
(Fig.  16) ;   the  temperature  mounts  at  every  slight  provoca- 


166 


THE    EMOTIONS 


tion  and  may  reach  the  incredible  height  of  110°  even. 
In  time,  the  entire  organism  is  destroyed — literally  con- 
sumed— by  the   concentration  of   dynamic   energy.     It  is 


Fig.  50. — Winner  of  Two-mile  Relay  Race. 
The  expression  is  like  that  of  anger  or  pain  about  to  change  to  that  of  exhaus- 
tion.    (Photo  by  Underwood  and  Underwood,  N.  Y.) 


interesting  to  note  that  in  these  patients  emotion  gains 
complete  possession  of  the  final  common  path;  they  are 
wild  and  delirious — but  they  never  have  pain. 

All  the  diseases  caused  by  excessive  motor  activity  may 


A   MECHANISTIC    THEORY    OF    DISEASE  167 

be  called  kinetic  diseases.     Against  the  conditions  in  life 
which  produce  them  man  reacts  in  various  ways.     He  intro- 


FiG.  51. — Cross-country  Race. 
Winner  of  six-mile  cross-country  race  showing  typical  expression  of  exhaus- 
tion.    (Copyright  by  Underwood  and  Underwood,  N.  Y.) 

duces  restful  variety  into  his  life  by  hunting  and  fishing ;  by 
playing  golf  and  tennis ;  by  horseback  riding;  by  cultivating 
hobbies  which  efTectually  turn  the  current  of  his  thoughts 


168 


THE    EMOTIONS 


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Fig.    53. — A   Cla.ssic   Coxceptiox   of   Fatigue — Phidippide.s,   the   First 

^Iarathon  Runner. 
"Athens  is  .saved!" — Phidippides  dies  in  the  shout  for  his  meed. — Browning. 

169 


170 


THE    EMOTIONS 


from  the  consuming  stress  and  strain  of  his  business  or  pro- 
fessional hfe.  These  diversions  are  all  rational  attempts  to 
relieve  tension  by  self -preservative  reactions.  For  the  same 
reason  man  attempts  to  relieve  the  strain  of  contention  with 


Fig.  54. — A  Modern  Marathon  Runner.     (Copyright  by  Underwood  and 

Underwood,  N.  Y.) 


his  fellow-man  by  unions,  trusts,  corporations.  In  spite  of 
all  efforts,  however,  many  constitutions  are  still  broken 
daily  in  the  fierce  conflicts  of  competition.  We  know  how 
often  the  overdriven  individual  endeavors  to  minimize  the 
activities  of  his  motor  mechanism  by  the  use  of  agents  which 


A    MECHANISTIC    THEORY    OF   DISEASE  171 

diminish  brain  activity,  such  as  alcohol,  tobacco,  and  various 
narcotics.  Occasionally  also,  some  person,  who  can  find  no 
respite  from  his  own  relentless  energies,  seeks  relief  in  ob- 
livion by  suicide. 

Most  fortunately,  two  fundamental  instincts — self-pres- 
ervation and  the  propagation  of  the  species — act  powerfully 
to  prevent  this  last  fatal  result,  and  instead  the  harassed 
indi\ddual  seeks  from  others  the  aid  which  is  lacking  within 
himself.  He  may  turn  to  the  priest  w^ho  seeks  and  often 
secures  the  final  common  path  for  faith  in  an  over-ruling 
Providence,  a  faith  which  in  many  incontrovertible  instances 
has  proved  sufficient  in  very  truth  to  move  mountains  of 
lesser  stimuli ;  or  he  turns  to  a  physician,  who  too  often  treats 
the  final  outcome  of  the  hyperactivity  only.  The  physician 
who  accepts  the  theory  of  the  kinetic  diseases,  however,  will 
not  only  repair  as  far  as  he  may  the  lesions  caused  by  the 
disordered  and  forced  activities,  but  will,  by  compelling  and 
forceful  suggestion,  secure  the  final  common  path  for  right 
conduct,  that  is,  for  a  self-  and  species-preservative  course 
of  action  as  opposed  to  wrong  conduct — a  self-  and  species- 
destructive  course  of  action. 

By  forcefully  imparting  to  his  patient  the  knowledge  of 
the  far-reaching  effects  of  protracted  emotional  strain,  of 
overwork,  and  of  worry,  the  physician  will  automatically 
raise  his  threshold  to  the  damaging  activating  stimuli  which 
have  produced  the  evil  results.  Even  though  some  parts  of 
his  organism  may  have  been  permanently  disabled,  a  patient 
thus  protected  may  yet  rise  to  a  plane  of  poise  and  efficiency 
far  above  that  of  his  uncontrolled  fellows. 

In  extreme  cases  it  does  not  seem  unreasonable  to  believe 
that  the  uncontrolled  patient  might  be  rescued  by  the  same 


172  THE    EMOTIONS 

principle  which  has  proved  effective  in  saving  patients  from 
the  emotional  and  traumatic  strain  of  surgical  operations — 
the  principle  of  anoci-association.  That  is,  by  disconnecting 
one  or  more  of  the  activating  organs  from  the  brain,  the 
motor  mechanism  might  be  saved  from  its  self-destruction. 
Under  this  hypothesis,  that  man  in  disease,  as  in  health,  is 
the  product  of  his  phylogeny  as  well  as  of  ontogeny,  the 
sphere  of  the  physician's  activities  takes  on  new  aspects  of 
far-reaching  and  inspiring  significance.  Prognosis  will  be- 
come definite  in  proportion  to  the  physician's  knowledge  not 
only  of  the  ontogenetic  history  of  the  individual  patient,  but 
also  of  the  phylogenetic  history  of  the  race.  As  that  knowl- 
edge increases,  as  he  appreciates  more  and  more  keenly  the 
significance  of  environment  in  its  effect  upon  individual 
development,  in  so  far  will  the  physician  be  in  a  position  to 
contribute  mightily  to  the  welfare  of  the  race. 


THE  KINETIC  SYSTEM* 

In  this  paper  I  formulate  a  theory  which  I  hope  will 
harmonize  a  large  number  of  chnical  and  experimental  data, 
supply  an  interpretation  of  certain  diseases,  and  show  by 
what  means  many  diverse  causes  produce  the  same  end 
effects. 

Even  should  the  theory  prove  ultimately  to  be  true,  it 
will  in  the  mean  time  doubtless  be  subjected  to  many  altera- 
tions. The  specialized  laboratory  worker  will,  at  first,  fail 
to  see  the  broader  clinical  view,  and  the  trained  chnician  may 
hesitate  to  accept  the  laboratory  findings.  Our  viewpoint 
has  been  gained  from  a  consideration  of  both  lines  of  evidence 
on  rather  a  large  scale. 

The  responsibihty  for  the  kinetic  theory  is  assumed  by 
myself,  while  the  responsibility  for  the  experimental  data  is 
shared  fully  by  my  associates,  Dr.  J.  B.  Austin,  Dr.  F.  W. 
Hitchings,  Dr.  H.  G.  Sloan,  and  Dr.  M.  L.  Menten.f 

Introduction 

The  self-preservation  of  man  and  kindred  animals  is 
effected  through  mechanisms  which  transform  latent  energy 
into  kinetic  energy  to  accomplish  adaptive  ends.  Man 
appropriates  from  environment  the  energy  he  requires  in  the 

*  Address  delivered  before  the  New  York  State  Medical  Society,  April  28, 
1914,  to  which  has  been  added  a  further  note  regarding  studies  of  hydrogen 
ion  concentration  in  the  blood. 

fFrom  H.  K.  Gushing  Laboratory  of  Experimental  Medicine,  Western 
Reserve  University,  Cleveland. 

173 


174  THE    EMOTIONS 

form  of  crude  food  which  is  refined  by  the  digestive  system; 
oxygen  is  taken  to  the  blood  and  carbon  dioxid  is  taken  from 
the  blood  by  the  respiratory  system;  to  and  from  the  myriads 
of  working  cells  of  the  body,  food  and  oxygen  and  waste  are 
carried  by  the  circulatory  system;  the  body  is  cleared  of 
waste  by  the  urinary  system;  procreation  is  accomplished 
through  the  genital  system;  but  none  of  these  systems  was 
evolved  primarily  for  the  purpose  of  transforming  potential 
energy  into  kinetic  energy  for  specific  ends.  Each  system 
transforms  such  amounts  of  potential  into  kinetic  energy 
as  are  required  to  perform  its  specific  work;  but  no  one  of 
them  transforms  latent  into  kinetic  energy  for  the  purposes 
of  escaping,  fighting,  pursuing,  nor  for  combating  infection. 
The  stomach,  the  kidneys,  the  lungs,  the  heart  strike  no 
physical  blow — their  role  is  to  do  certain  work  to  the  end 
that  the  blow  may  be  struck  by  another  system  evolved  for 
that  purpose.  I  propose  to  offer  evidence  that  there  is  in 
the  body  a  system  evolved  primarily  for  the  transformation 
of  latent  energy  into  motion  and  into  heat.  This  system  I 
propose  to  designate  "The  Kinetic  System." 

The  kinetic  system  does  not  directly  circulate  the  blood, 
nor  does  it  exchange  oxygen  and  carbon  dioxid;  nor  does  it 
perform  the  functions  of  digestion,  urinary  ehmination,  and 
procreation ;  but  though  the  kinetic  system  does  not  directly 
perform  these  functions,  it  does  play  indirectly  an  important 
role  in  each,  just  as  the  kinetic  system  itself  is  aided  indirectly 
by  the  other  systems. 

The  principal  organs  which  comprise  the  kinetic  system 
are  the  brain,  the  thyroid,  the  adrenals,  the  liver,  and  the 
muscles.  The  brain  is  the  great  central  battery  which 
drives  the  body;  the  thyroid  governs  the  conditions  favoring 


THE    KINETIC    SYSTEM  175 

tissue  oxidation;  the  adrenals  govern  immediate  oxida- 
tion processes ;  the  liver  fabricates  and  stores  glycogen;  and 
the  muscles  are  the  great  converters  of  latent  energy  into 
heat  and  motion. 

Adrenalin  alone,  thyroid  extract  alone,  brain  activity 
alone,  and  muscular  activity  alone  are  capable  of  causing 
the  body  temperature  to  rise  above  the  normal.  The 
functional  activity  of  no  other  gland  of  the  body  alone,  and 
the  secretion  of  no  other  gland  alone,  can  cause  a  comparable 
rise  in  body  temperature — that  is,  neither  increased  func- 
tional activity  nor  any  active  principle  derived  from  the 
kidney,  the  liver,  the  stomach,  the  pancreas,  the  hypophysis, 
the  parathyroids,  the  spleen,  the  intestines,  the  thymus,  the 
lymphatic  glands,  or  the  bones  can,  per  se,  cause  a  rise  in  the 
general  body  temperature  comparable  to  the  rise  that  may 
be  caused  by  the  activity  of  the  brain  or  the  muscles,  or  by 
the  injection  of  adrenalin  or  thyroid  extract.  Then,  too, 
when  the  brain,  the  thyroid,  the  adrenals,  the  liver,  or  the 
muscles  are  eliminated,  the  power  of  the  body  to  convert 
latent  into  kinetic  energy  is  impaired  or  lost.  I  shall  offer 
evidence  tending  to  show  that  an  excess  of  either  internal 
or  external  environmental  stimuli  may  modify  one  or  more 
organs  of  the  kinetic  system,  and  that  this  modification 
may  cause  certain  diseases.  For  example,  alterations  in  the 
efficiency  of  the  cerebral  link  may  yield  neurasthenia,  mania, 
dementia;  of  the  thyroid  link,  Graves'  disease,  myxedema; 
of  the  adrenal  link,  Addison's  disease,  cardiovascular  disease. 

This  introduction  may  serve  to  give  the  line  of  our  argu- 
ment. We  shall  now  consider  briefly  certain  salient  facts 
which  relate  to  the  conversion  of  latent  into  kinetic  energy 


176  THE    EMOTIONS 

as  an  adaptive  reaction.     The  experimental  data  are  so 
many  that  they  will  later  be  published  in  a  monograph. 

The  amount  of  latent  energy  which  may  be  converted  into 
kinetic  energy  for  adaptive  ends  varies  in  different  species, 
in  individuals  of  the  same  species,  in  the  same  individual  in 
different  seasons;  in  the  hfe  cycle  of  growth,  reproduction 
and  decay;  in  the  waking  and  sleeping  hours;  in  disease  and 
in  activity.  We  shall  here  consider  briefly  the  reasons  for 
some  of  those  variations  and  the  mechanisms  which  make 
them  possible. 


Biologic  Consideration  of  the  Adaptive  Variation  in  Amounts  of 
Energy   Stored   in  Various   Animals 

Energy  is  appropriated  from  the  physical  forces  of  nature 
that  constitute  the  environment.  This  energy  is  stored  in 
the* body  in  quantities  in  excess  of  the  needs  of  the  moment. 
In  some  animals  this  excess  storage  is  greater  than  in  other 
animals.  Those  animals  whose  self-preservation  is  depen- 
dent on  purely  mechanical  or  chemical  means  of  defense — 
such  animals  as  crustaceans,  porcupines,  skunks  or  cobras — 
have  a  relatively  small  amount  of  convertible  (adaptive) 
energy  stored  in  their  bodies.  On  the  contrary,  the  more 
an  animal  is  dependent  on  its  muscular  activity  for  self- 
preservation,  the  more  surplus  available  (adaptive)  energy 
there  is  stored  in  its  body.  It  may  be  true  that  all  animals 
have  approximately  an  equal  amount  per  kilo  of  chemical 
energy — but  certainly  they  have  not  an  equal  amount  stored 
in  a  form  which  is  available  for  immediate  conversion  for 
adaptive  ends. 


THE    KINETIC    SYSTEM  177 

Adaptive  Variation  in  the  Rate  of  Energy  Discharge 
What  chance  for  survival  would  a  skunk  have  without 
odor;  a  cobra  without  venom;  a  turtle  without  carapace; 
or  a  porcupine  shorn  of  its  barbs,  in  an  environment  of  power- 
ful and  hostile  carnivora?  And  yet  in  such  an  hostile  en- 
vironment many  unprotected  animals  survive  by  their 
muscular  power  of  flight  alone.  It  is  evident  that  the  pro- 
vision for  the  storage  of  "adaptive"  energy  is  not  the  only 
evolved  characteristic  which  relates  to  the  energy  of  the 
body.  The  more  the  self-preservation  of  the  animal  de- 
pends on  motor  activity,  the  greater  is  the  range  of  variation 
in  the  rate  of  discharge  of  energy.  The  rate  of  energy  dis- 
charge is  especially  high  in  animals  evolved  along  the  line  of 
hunter  and  hunted,  such  as  the  carnivora  and  the  herbivora 
of  the  great  plains. 

Influences  That  Cause  Variation  in  the  Rate  of  Owtpwt  of  Energy 
in  the  Individual 

Not  only  is  there  a  variation  in  the  rate  of  output  of  energy 
among  various  species  of  animals,  but  one  finds  also  varia- 
tions in  the  rate  of  output  of  energy  among  individuals  of 
the  same  species.  If  our  thesis  that  men  and  animals  are 
mechanisms  responding  to  environmental  stimuli  be  correct, 
and  further,  if  the  speed  of  energy  output  be  due  to  changes 
in  the  activating  organs  as  a  result  of  adaptive  stimulation, 
then  we  should  expect  to  find  physical  changes  in  the  activat- 
ing glands  during  the  cycles  of  increased  activation.  What 
are  the  facts?  We  know  that  most  animals  have  breeding 
seasons  evolved  as  adaptations  to  the  food  supply  and 
weather.     Hence  there  is  in  most  animals  a  mating  season 

12 


178  THE    EMOTIONS 

in  advance  of  the  season  of  maximum  food  supply  so  that  the 
young  may  appear  at  the  period  when  food  is  most  abundant. 
In  the  springtime  most  birds  and  mammals  mate,  and  in  the 
springtime  at  least  one  of  the  great  activating  glands  is 
enlarged — the  th^Toid  in  man  and  in  animals  shows  seasonal 
enlargement.  The  effect  of  the  increased  activity  is  seen 
in  the  song,  the  courting,  the  fighting,  in  the  quickened  pulse, 
and  in  a  shghtly  raised  temperature.  Even  more  activation 
than  that  connected  \^ith  the  season  is  seen  in  the  physical 
state  of  mating,  when  the  th^Toid  is  known  to  enlarge 
materially,  though  this  increased  activitj^,  as  we  shall  show 
later,  is  probably  no  greater  than  the  increased  activity  of 
other  activating  glands.  In  the  mating  season  the  kinetic 
acti^itj^  is  speeded  up;  in  short,  there  exists  a  state — a 
fleeting  state — of  mild  Graves'  disease.  In  the  early  stages 
of  Graves'  disease,  before  the  destructive  phenomena  are 
felt,  the  kinetic  speed  is  high,  and  life  is  on  a  sensuous  edge. 
Not  only  is  there  a  seasonal  rhj^hm  to  the  rate  of  flow  of 
energy,  but  there  is  a  diurnal  variation — the  ebb  is  at  night, 
and  the  fuU  tide  in  the  dajiiime.  This  observation  is  verified 
b}^  the  experiments  which  show  that  certain  organs  in  the 
kinetic  chain  are  histologically  exhausted,  the  depleted  cells 
being  for  the  most  part  restored  by  sleep. 

We  have  seen  that  there  are  variations  in  speed  in  different 
species,  and  that  in  the  same  species  speed  varies  mth  the 
season  of  the  A^ear  and  with  the  time  of  day.  In  addition 
there  are  variations  also  in  the  rate  of  discharge  of  energy 
in  the  various  cycles  of  the  fife  of  the  individual.  The  young 
are  evolved  at  high  speed  for  growth,  so  that  as  soon  as 
possible  they  may  attain  to  their  o^^m  power  of  self-defense; 
they  must   adapt   themselves  to  innumerable  bacteria,  to 


THE    KINETIC    SYSTEM  179 

food,  and  to  all  the  elements  in  their  external  environment. 
Against  their  gross  enemies  the  young  are  measurably  pro- 
tected by  their  parents;  but  the  parents — except  to  a  Hmited 
extent  in  the  case  of  man — are  unable  to  assist  in  the  pro- 
tection of  the  young  against  infectious  disease. 

The  cycle  of  greatest  kinetic  energy  for  physiologic  ends 
is  the  period  of  reproduction.  In  the  female  especially  there 
is  a  cycle  of  increased  activity  just  prior  to  her  development 
into  the  procreative  state.  During  this  time  secondary 
sexual  characters  are  developed — the  pelvis  expands,  the 
ovaries  and  the  uterus  grow  rapidly,  the  mammary  glands 
develop.  Again  in  this  period  of  increasing  speed  in  the 
expenditure  of  energy  we  find  the  thjToid,  the  adrenals,  and 
the  hypophysis  also  in  rapid  growth.  Without  the  normal 
development  of  the  ovary,  the  thyroid,  and  the  hypophysis, 
neither  the  male  nor  the  female  can  develop  the  secondary 
sexual  characters,  nor  do  they  develop  sexual  desire  nor 
show  seasonal  cycles  of  activity,  nor  can  they  procreate. 
The  secondary  sexual  characters — sexual  desire,  fertility — 
may  be  developed  at  will,  for  example,  by  feeding  th\Toid 
products  from  alien  species  to  the  individual  deprived  of  the 
thjToid. 

At  the  close  of  the  child-bearing  period  there  is  a  perma- 
nent diminution  of  the  speed  of  energy  discharge,  for  energy 
is  no  longer  needed  as  it  was  for  the  self-preservation  of  the 
offspring  before  adolescence,  and  for  the  propagation  of  the 
species  during  the  procreative  period.  Unless  other  factors 
intervene,  this  reduction  in  speed  is  progressive  until  senes- 
cent death.  The  diminished  size  of  the  thyroid  of  the  aged 
bears  testimony  to  the  part  the  activating  organs  bear  in  the 
general  decline. 


180  THE    EMOTIONS 

We  have  now  referred  to  variations  in  the  rate  of  dis- 
charge of  energy  in  different  species;  in  individuals  of  the 
same  species;  in  cycles  in  the  same  individual — such  as  the 
seasons  of  food  supply,  the  periods  of  wakefulness  and  of 
sleep,  the  procreative  period,  and  we  have  spoken  of  those 
variations  caused  artificially  by  thyroid  feeding,  thus  far 
having  confined  our  discussion  to  the  conversion  for  adap- 
tive purposes  of  latent  into  kinetic  energy  in  muscular  and  in 
procreative  action.  We  shall  now  consider  the  conversion  of 
latent  into  kinetic  energy  in  the  production  of  heat,*  and 
endeavor  to  answer  the  questions  which  arise  at  once:  Is 
there  one  mechanism  for  the  conversion  of  latent  energy  into 
heat  and  another  mechanism  for  its  conversion  into  muscular 
action?  What  is  the  adaptive  advantage  of  fever  in  in- 
fection? 

The  Purpose  and  the  Mechanism  of  Heat  Production  in  Infections 
Vaughan  has  shown  that  the  presence  in  the  body  of  any 
alien  protein  causes  an  increased  production  of  heat,  and 
that  there  is  no  difference  between  the  production  of  fever  by 
foreign  proteins  and  by  infections.  Before  the  day  of  the 
hypodermic  needle  and  of  experimental  medicine,  the  foreign 
proteins  found  in  the  body  outside  the  alimentary  tract  were 
brought  in  by  invading  microorganisms.  Such  organisms 
interfered  with  and  destroyed  the  host.  The  body,  there- 
fore, was  forced  to  evolve  a  means  of  protection  against  these 
hostile  organisms.  The  increased  metabolism  and  fever 
in  infection  might  operate  as  a  protection  in  two  ways — the 
increased  fever,  by  interfering  with  bacterial  growth,  and  the 

*  We  use  the  terms  "heat"  and  "muscular  action"  in  the  popular  sense, 
though  physicists  use  them  to  designate  one  and  the  same  kind  of  energy. 


THE    KINETIC    SYSTEM  181 

increased  metabolism,  by  breaking  up  the  bacteria.  Bacteri- 
ologists have  taught  us  that  bacteria  grow  best  at  the  normal 
temperature  of  the  body,  hence  fever  must  interfere  with 
bacterial  growth.  With  each  rise  of  one  degree  centigrade 
the  chemical  activity  of  the  body  is  increased  10  per  cent. 
In  acute  infections  there  is  aversion  to  food  and  frequently 
there  is  vomiting.  In  fever,  then,  we  have  diminished  in- 
take of  energy,  but  an  increased  output  of  energy — hence  the 
available  potential  energy  in  the  body  is  rapidly  consumed. 
This  may  be  an  adaptation  for  the  purpose  of  breaking  up 
the  foreign  protein  molecules  composing  the  bacteria.  Thus 
the  body  may  be  purified  by  a  chemical  combustion  so  furious 
that  frequently  the  host  itself  is  destroyed.  The  problems 
of  immunity  are  not  considered  here. 

As  to  the  mechanism  which  produces  fever,  we  postulate 
that  it  is  the  same  mechanism  as  that  which  produces  muscu- 
lar activity.  Muscular  activity  is  produced  by  the  con- 
version of  latent  energy  into  motion,  and  fever  is  produced 
largely  in  the  muscles  by  the  conversion  of  latent  energy 
into  heat.  We  should,  therefore,  find  similar  changes  in  the 
brain,  the  adrenals,  the  thyroid,  and  the  liver,  whatever  may 
be  the  purpose  of  the  conversion  of  energy — whether  for  run- 
ning, for  fighting,  for  the  expression  of  emotion,  or  for  com- 
bating infection. 

We  shall  first  present  experimental  and  clinical  evidence 
which  tends  to  show  what  part  is  played  by  the  brain  in  the 
production  of  both  muscular  and  febrile  action,  and  later 
we  shall  discuss  the  parts  played  by  the  adrenals,  the 
thyroid,  and  the  liver. 


182  THE    EMOTIONS 


Histologic  Changes  in  the  Brain-cells  in  Relation  to  the  Main- 
tenance of  Consciousness  and  to  the  Production  of  the  Emo- 
tions, Mtisctjlar  Activity,  and  Fever 

We  have  studied  the  brain-cells  in  human  cases  of  fever, 
and  in  animals  after  prolonged  insomnia;  after  the  injection 
of  the  toxins  of  gonococci,  of  streptococci,  of  staphylococci, 
and  of  colon,  tetanus,  diphtheria,  and  typhoid  bacilli;  and 
after  the  injection  of  foreign  proteins,  of  indol  and  skatol, 
of  leucin,  and  of  peptones.  We  have  studied  the  brains  of 
animals  which  had  been  activated  in  varying  degrees  up  to 
the  point  of  complete  exhaustion  by  running,  by  fighting, 
by  rage  and  fear,  by  physical  injury,  and  by  the  injection  of 
strychnin  (Figs.  2,  4,  5,  and  37).  We  have  studied  the 
brains  of  salmon  at  the  mouth  of  the  Columbia  River  and  at 
its  headwater  (Fig.  55) ;  the  brains  of  electric  fish,  the  storage 
batteries  of  which  had  been  partially  discharged,  and  of 
those  the  batteries  of  which  had  been  completely  discharged; 
the  brains  of  woodchucks  in  hibernation  and  after  fighting; 
the  brains  of  humans  who  had  died  from  anemia  resulting 
from  hemorrhage,  from  acidosis,  from  eclampsia,  from  can- 
cer and  from  other  chronic  diseases  (Figs.  40  to  43,  56,  74, 
and  75).  We  have  studied  also  the  brains  of  animals  after 
the  excision  of  the  adrenals,  of  the  pancreas,  and  of  the 
liver  (Figs.  57  and  60). 

In  every  instance  the  loss  of  vitality — that  is,  the  loss  of 
the  normal  power  to  convert  potential  into  kinetic  energy — 
was  accompanied  by  physical  changes  in  the  brain-cells 
(Figs.  45  and  46).  The  converse  was  also  true,  that  is,  the 
brain-cells  of  animals  with  normal  vital  power  showed  no 
histologic   changes.     The  changes  in  the  brain-cells  were 


THE    KINETIC    SYSTEM  183 

identical  whatever  the  cause.  The  crucial  question  then 
becomes:  Are  these  constant  changes  in  the  brain-cells  the 
result  of  work  done  by  the  brain-cells  in  running,  in  fighting, 
in  emotion,  in  fever?     In  other  words,  does  the  brain  per- 


g> ;/    ♦' 

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r^  9 

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'  ^ 

A  B 

Area  from  Cerebellum  of  Male  Salmon  Area  from  Cerebellum  of  Male  Salmon 

from  Ocean.  from  the  River. 

Fig.  55. — Exhaustion  of  Brain-cells  of  Salmon  Caused  by  Expenditure 
OF  Energy  in  Swimming  from  the  Ocean  to  the  Head  Waters  of 
Columbia  River.     (Camera  lucida  drawings.) 

form  a  definite  role  in  the  conversion  of  latent  energy  into 
fever  or  into  muscular  action ;  or  are  the  brain-cell  changes 
caused  by  the  chemical  products  of  metabolism?     Happily, 


184 


THE   EMOTIONS 


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THE   KINETIC    SYSTEM 


185 


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186 


THE    EMOTIONS 


this  crucial  question  was  definitely  answered  by  the  follow- 
ing experiment :  The  circulations  of  two  dogs  were  crossed 
in  such  a  manner  that  the  circulation  of  the  head  of  one  dog 
was  anastomosed  with  the  circulation  of  the  body  of  another 
dog,  and  vice  versa.  A  cord  encircled  the  neck  of  each  so 
firmly  that  the  anastomosing  circulation  was  blocked  (Fig. 
58) .  If  the  brain-cell  changes  were  due  to  metabolic  prod- 
ucts, then  when  the  body  of  dog  ''A"   was  injured,  the 


"n0ORNlC).UE.T 


DOG 
A. 


DOGi 


COMMON    CAROTIDS 
AND  EXTEF?NAU 
JUGULARS. 


TooR^^lOuer 


Fig.  58. — Schematic  Drawing,  showing  Course  of  Blood-stream  of  Two 
Dogs  with  Eight- vessel  Crossed  Circulation. 


brain  of  dog  ''A"  would  be  normal  and  the  brain  of  dog 
''B"  would  show  changes.  Our  experiments  showed  brain- 
cell  changes  in  the  brain  of  the  dog  injured  and  no  changes 
in  the  brain  of  the  uninjured  dog. 

The  injection  of  adrenahn  causes  striking  brain-cell 
changes:  first,  a  hyperchromatism,  then  a  chromatolysis. 
Now  if  adrenalin  caused  these  changes  merely  as  a  metabolic 


THE    KINETIC    SYSTEM 


187 


phenomenon  and  not  as  a  ''work"  phenomenon,  then  the 
injection  of  adrenahn  into  the  carotid  artery  of  a  crossed 
circulation  dog  would  cause  no  change  in  its  circulation  and 
its  respiration,  since  the  brain  thus  injected  is  in  exclusive 
vascular  connection  with  the  body  of  another  dog.  In  our 
experiment  the  blood-pressures  of  both  dogs  were  recorded 


Fig.  59. — Blood-pressure  Tracing  Demonstrating  that  in  Spite  of  Fact 
THAT  Blood  of  Dog  "A"  Passed  Through  Brain  of  Dog  "B,"  Yet 
Brain  of  Dog  "A"  Received  the  Stimulation  Caused  by  Injection 
of  Adrenalin  into  Blood  of  Dog  "A." 

on  a  drum  when  adrenahn  was  injected  into  the  common 
carotid.  The  adrenahn  caused  a  rise  in  blood-pressure,  an 
increase  in  the  force  of  cardiac  contraction,  increase  in  res- 
piration, and  a  characteristic  adrenahn  rise  in  the  blood- 
pressure  of  both  dogs.  The  rise  was  seen  first  in  the  dog 
whose  brain  alone  received  adrenahn  and  about  a  minute 


188  THE    EMOTIONS 

later  in  the  dog  whose  body  alone  received  adrenalin  (Fig. 
59).  Histologic  examinations  of  the  brains  of  both  dogs 
showed  marked  hyperchromatism  in  the  brain  receiving 
adrenalin,  while  the  brain  receiving  no  adrenalin  showed  no 
change.  Here  is  a  clear-cut  observation  on  the  action  of 
adrenalin  on  the  brain,  for  both  the  functional  and  the 
histologic  tests  showed  that  adrenalin  causes  increased  brain 
action.  The  significance  of  this  affinity  of  the  brain  for 
adrenalin  begins  to  be  seen  when  I  call  attention  to  the  fol- 
lowing striking  facts : 

1.  Adrenalin  alone  causes  hyperchromatism  followed  by 
chromatolysis,  and  in  overdosage  causes  the  destruction  of 
some  brain-cells. 

2.  When  both  adrenal  glands  are  excised  and  no  other 
factor  is  introduced,  the  Nissl  substance  progressively  dis- 
appears from  the  brain-cells  until  death.  This  far-reaching 
point  will  be  taken  up  later  (Fig.  60) . 

Here  our  purpose  is  to  discuss  the  cause  of  the  brain-cell 
changes.  We  have  seen  that  in  crossed  brain  and  body 
circulation  trauma  causes  changes  in  the  cells  of  the  brain 
which  is  disconnected  from  the  traumatized  body  by  its 
circulation,  but  which  is  connected  with  the  traumatized 
body  by  the  nervous  system.  We  have  seen  that  adrenalin 
causes  activation  of  the  body  connected  with  its  brain  by 
the  nervous  system,  and  histologic  changes  in  the  brain 
acted  on  directly  by  the  adrenalin,  but  we  found  no  notable 
brain-cell  changes  in  the  other  brain  through  which  the 
products  of  metabolism  have  circulated. 

In  the  foregoing  we  find  direct  evidence  that  the  products 
of  metabolism  are  not  the  principal  cause  of  the  brain-cell 
changes.     We  shall  now  present  evidence  to  show  that  for 


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190 


THE    EMOTIONS 


the  most  part  the  brain-cell  changes  are  ''work"  changes. 
What  work?  We  postulate  that  it  is  the  work  by  which  the 
energy  stored  in  the  brain-cells  is  converted  into  electric- 
ity or  some  other  form  of  transmissible  energy  which  then 
activates  certain  glands  and  muscles,  thus  converting  latent 
energy  into  heat  and  motion.     It  has  chanced  that  certain 


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Area  from  Cerebellum 

of 

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Fish — Exhausted. 

Area  from    Cerebellum    of    Electric 
Fish — Normal. 

Fig.  61. — ^Exhaustion  of  Brain-cells  of  Electric  Fish  Caused  by  Ex- 
penditure OF  Energy  in  Making  Electric  Discharges. 


other  studies  have  given  an  analogous  and  convincing  proof 
of  this  postulate.  In  the  electric  fish  a  part  of  the  muscular 
mechanism  is  replaced  by  a  specialized  structure  for  storing 
and  discharging  electricity.  We  found  "work"  changes  in 
the  brain-cells  of  electric  fish  after  all  their  electricity  had 
been  rapidly  discharged  (Fig.  61).  We  found  further  that 
electric  fish  could  not  discharge  their  electricity  when  under 


THE    KINETIC    SYSTEM  191 

anesthesia,  and  clinically  we  know  that  under  deep  morphin 
narcosis,  and  under  anesthesia,  the  production  both  of  heat 
and  of  muscular  action  is  hindered.  The  action  of  morphin 
in  lessening  fever  production  is  probably  the  result  of  its 
depressing  influence  on  the  brain-cells,  because  of  which  a 
diminished  amount  of  their  potential  energy  is  converted 
into  electricity  and  a  diminished  electric  discharge  from  the 
brain  to  the  muscles  should  diminish  heat  production  propor- 
tionally. We  found  by  experiment  that  under  deep  mor- 
phinization  brain-cell  changes  due  to  toxins  could  be  largely 
prevented  (Fig.  62);  in  human  patients  deep  morphiniza- 
tion  diminishes  the  production  of  muscular  action  and  of 
fever,  and  conserves  life  when  it  is  threatened  by  acute 
infections.  The  contribution  of  the  brain-cells  to  the  pro- 
duction of  heat  is  either  the  result  of  the  direct  conversion 
of  their  stored  energy  into  heat,  or  of  the  conversion  of 
their  latent  energy  into  electricity  or  a  similar  force,  which 
in  turn  causes  certain  glands  and  muscles  to  convert  latent 
energy  into  heat. 

A  further  support  to  the  postulate  that  the  brain-cells 
contribute  to  the  production  of  fever  by  sending  impulses  to 
the  muscles  is  found  in  the  effect  of  muscular  exertion,  or  of 
other  forms  of  motor  stimulation,  in  the  presence  of  a  fever- 
producing  infection.  Under  such  circumstances  muscular 
exertion  causes  additional  fever,  and  causes  also  added  but 
identical  changes  in  the  brain-cells.  Thyroid  extract  and 
iodin  have  the  same  effect  as  muscular  exertion  and  infection 
in  the  production  of  fever  and  the  production  of  brain-cell 
changes.  All  this  evidence  is  a  strong  argument  in  favor 
of  the  theory  that  certain  constituents  of  the  brain-cells 


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192 


THE    KINETIC    SYSTEM 


193 


are  consumed  in  the  work  performed  by  the  brain  in  the 
production  of  fever. 

That  the  stimulation  of  the  brain-cells  without  gross 
activity  of  the  skeletal  muscles  and  without  infection  can 
produce  heat  is  shown  as  follows : 

(a)  Fever  is  produced  when  animals  are  subjected  to  fear 
without  any  consequent  exertion  of  the  skeletal  muscles. 

(b)  The  temperature  of  the  anxious  friends  of  patients 


n.J.cfi 

60 

Zoo 

/20 

/VO 

^6e 

0/ 

Fa-trent  v^itk 
Exopb.  Goiter 

before    op  e 

ra.tio  n 

After  cperdJ 

10  n. 

of 

Seforc  opard. 

hen 

Af/er  opera- 

tlOTL 

Fia.  63. — Chart  Illustrating  Protection  Afforded  by  Use  of  Anoci- 
association  in  Thyroidectomy. 
The  patient's  brain  received  neither  traumatic  nor  psychic  stimuli  from 
the  time  she  was  anesthetized  in  bed  until  she  returned  again  from  the  operating- 
room.  Her  pulse-rate  fell  slightly  during  the  operation.  On  the  other  hand, 
the  psychic  strain  undergone  by  the  patient's  sister  while  the  operation  was 
being  performed  caused  her  pulse-rate  to  rise  to  124. 


will  rise  while  they  await  the  outcome  of  an  operation  (Fig. 
63). 

(c)  The  temperature  and  pulse  of  patients  will  rise  as  a 
result  of  the  mere  anticipation  of  a  surgical  operation  (Fig.  64) . 

(d)  There  are  innumerable  clinical  observations  as  to  the 
effect  of  emotional  excitation  on  the  temperature  of  patients. 
A  rise  of  a  degree  or  more  is  a  common  result  of  a  visit  from 
a  tactless  friend.  There  is  a  traditional  Sunday  increase  of 
temperature  in  hospital  wards.     Now  the  visitor  does  not 

13 


194 


THE    EMOTIONS 


TEMPERATURE 

lOl" 

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Fig.  64. — The  patient,  a  foreigner,  was  brought  to  the  operating-room 
from  the  accident  ward.  Pulse  and  temperature  normal.  When  he  found 
himself  in  the  operating-room  he  was  greatly  disturbed.  It  was  impossible 
to  make  him  understand  that  his  leg  was  not  to  be  amputated  but  only  a 
plaster  cast  applied.  Under  this  stimulus  his  pulse  rose  to  150  and  he  soon  de- 
veloped a  temperature  of  101.2°  F. 


THE    KINETIC    SYSTEM  195 

bring  and  administer  more  infection  to  the  patient  to  cause 
this  rise,  and  the  rise  of  temperature  occurs  even  if  the 
patient  does  not  make  the  least  muscular  exertion  as  a  result 
of  the  visit.  I  once  observed  an  average  increase  of  one  and 
one-eighth  degrees  of  temperature  in  a  ward  of  fifteen  chil- 
dren as  a  result  of  a  Fourth  of  July  celebration. 

Is  the  contribution  of  the  brain  to  the  production  of  heat 
due  to  the  conversion  of  latent  energy  directly  into  heat,  or 
does  the  brain  produce  heat  principally  by  converting  its 
latent  energy  into  electricity  or  some  similar  form  of  trans- 
missible energy  which,  through  nerve  connections,  stimu- 
lates other  organs  and  tissues,  which  in  turn  convert  their 
stores  of  latent  energy  into  heat? 

According  to  Starling,  when  the  connection  between  the 
brain  and  the  muscles  of  an  animal  is  severed  by  curare,  by 
anesthetics,  by  the  division  of  the  cord  and  nerves,  then  the 
heat-producing  power  of  the  animal  so  modified  is  on  a  level 
with  that  of  cold-blooded  animals.  With  cold  the  tempera- 
ture falls,  with  heat  it  rises.  Such  an  animal  has  no  more 
control  over  the  conversion  of  latent  energy  into  heat  than 
it  has  over  the  conversion  of  latent  energy  into  motion. 

Electric  stimulation  done  over  a  period  of  time  causes 
brain-cell  changes,  and  electric  stimulation  of  the  muscles 
causes  a  rise  in  temperature. 

Sammary  of  Brain-ccII  Stadies 
In  our  crossed  circulation  experiments  we  found  that 
neither  waste  products  nor  metabolic  poisons  could  be  con- 
sidered the  principal  cause  of  the  brain-cell  changes.  We 
found  that  in  the  production  both  of  muscular  action  and  of 
fever  there  were  brain-cell  changes  which  showed  a  quantita- 


196  THE    EMOTIONS 

tive  relation  to  the  temperature  changes  or  to  the  muscular 
work  done.  We  observed  that  under  deep  morphinization 
the  febrile  response  or  the  muscular  work  done  was  either 
diminished  or  eliminated  and  that  the  brain-cell  changes  were 
correspondingly  diminished  or  eliminated.  We  found  also 
that  brain-cell  changes  and  muscular  work  followed  electric 
stimulation  alone.  I  conclude,  therefore,  that  the  brain- 
cell  changes  are  work  changes. 

We  shall  next  consider  other  organs  of  the  kinetic  system 
in  their  relation  to  muscular  activity,  to  emotion,  to  con- 
sciousness, to  sleep,  to  hibernation,  and  to  heat  production. 

The  Adrenals 

In  our  extensive  study  of  the  brain  in  its  relation  to  the 
production  of  energy  and  the  consequent  exhaustion  caused 
by  fear  and  rage;  by  the  injection  of  foreign  proteins,  of 
bacterial  toxins,  and  of  strychnin;  by  anaphylaxis;  by  the 
injection  of  thyroid  extract,  of  adrenalin,  and  of  morphin, 
we  found  that,  with  the  exception  of  morphin,  each  of  these 
agents  produced  identical  changes  in  the  brain-cells.  As  we 
believed  that  the  adrenals  were  intimately  associated  with 
the  brain  in  its  activities,  we  concluded  that  the  adrenals 
also  must  have  been  affected  by  each  of  these  agents.  To 
prove  this  relation,  we  administered  the  above-mentioned 
stimuli  to  animals  and  studied  their  effects  upon  the  adrenals 
by  functional,  histologic,  and  surgical  methods,  the  func- 
tional tests  being  made  by  Cannon's  method. 

Functional  Study  of  the  Adrenals. — Our  method  of  ap- 
plying the  Cannon  test  for  adrenalin  was  as  follows:  (a) 
The  blood  of  the  animals  was  tested  before  the  application 
of  the  stimulus.     If  this  test  was  negative,  then   (6)   the 


THE    KINETIC    SYSTEM  197 

stimulus  was  applied  and  the  blood  again  tested.  If  this 
second  test  was  negative,  a  small  amount  of  adrenalin  was 
added.  If  a  positive  reaction  was  then  given,  the  negative 
result  was  accepted  as  conclusive,  (c)  If  the  control  test 
was  negative,  then  the  stimulus  was  given.  If  the  blood 
after  stimulation  gave  a  positive  result  for  adrenalin,  a 
second  test  of  the  same  animal's  blood  was  made  twenty-five 
minutes  or  more  later.  If  the  second  test  was  negative, 
then  the  positive  result  of  the  first  test  was  accepted  as  con- 
clusive. 

We  have  recorded  66  clear-cut  experiments  on  dogs, 
which  show  that  after  fear  and  rage,  after  anaphylaxis, 
after  injections  of  indol  and  skatol,  of  leucin  and  creatin,  of 
the  toxins  of  diphtheria  and  colon  bacilli,  of  streptococci 
and  staphylococci,  of  foreign  proteins,  and  of  strychnin,  the 
Cannon  test  for  adrenalin  was  positive.  The  test  was 
negative  after  trauma  under  anesthesia,  and  after  intraven- 
ous injections  of  thyroid  extract,  of  thyroglobin,  and  of  the 
juices  of  various  organs  injected  into  the  same  animal  from 
which  the  organs  were  taken.  Placental  extract  gave  a 
positive  test.  The  test  was  sometimes  positive  after  electric 
stimulation  of  the  splanchnic  nerves.  On  the  other  hand,  if 
the  nerve  supply  to  the  adrenals  had  been  previously  di- 
vided, or  if  the  adrenals  had  been  previously  excised,  then 
the  Cannon  test  was  negative  after  the  administration  of 
each  of  the  foregoing  adequate  stimuli.  Blood  taken  di- 
rectly from  the  adrenal  vein  gave  a  positive  result,  but  under 
deep  morphinization  the  blood  from  the  adrenal  vein  was 
negative,  and  under  deep  morphinization  the  foregoing 
adequate  stimuli  were  negative. 

In  brief,  the  agencies  that  in  our  brain-cell  studies  were 


198  THE    EMOTIONS 

found  to  cause  hyperchromatism  followed  by  chromatolysis 
gave  positive  results  in  the  Cannon  test  for  adrenalin  (Fig. 
62).  The  one  agent  which  was  found  to  protect  the  brain 
against  changes  in  the  Nissl  substance — morphin — gave  a 
negative  result  in  the  Cannon  test  for  adrenalin.  After 
excision  of  the  adrenals,  or  after  division  of  their  nerve  sup- 
ply, all  Cannon  tests  for  adrenalin  were  negative. 

Histologic  Study  of  the  Adrenals. — Histologic  studies 
of  the  adrenals  after  the  application  of  the  adequate  stimuli 
which  gave  positive  results  to  the  Cannon  test  for  adrena- 
lin are  now  in  progress,  and  thus  far  the  histologic  studies 
corroborate  the  functional  tests. 

In  hibernating  woodchucks,  the  cells  of  the  adrenal  cortex 
were  found  to  be  vacuolated  and  shrunken.  In  one  hundred 
hours  of  insomnia,  in  surgical  shock,  in  strong  fear,  in  exhaus- 
tion from  fighting,  after  peptone  injections,  in  acute  infec- 
tions, the  adrenals  undergo  histologic  changes  characteristic 
of  exhaustion  (Figs.  66  to  67). 

We  have  shown  that  brain  and  adrenal  activity  go  hand 
in  hand,  that  is,  that  the  adrenal  secretion  activates  the 
brain,  and  that  the  brain  activates  the  adrenals.  The  funda- 
mental question  which  now  arises  is  this:  Are  the  brain  and 
the  adrenals  interdependent?  A  positive  answer  may  be 
given  to  this  question,  for  the  evidence  of  the  dependence  of 
the  brain  upon  the  adrenals  is  as  clear  as  is  the  evidence  of 
the  dependence  of  the  adrenals  upon  the  brain.  (1)  After 
excision  of  the  adrenals,  the  brain-cells  undergo  continu- 
ous histologic  and  functional  deterioration  until  death. 
During  this  time  the  brain  progressively  loses  its  power  to 
respond  to  stimuli  and  there  is  also  a  progressive  loss  of 
muscular  power  and  a  diminution  of  body  temperature.     (2) 


THE    KINETIC    SYSTEM 


199 


Cells  from  normal  cerebellum.     Cells  from  cerebellum     Ceils     from      cerebellum 


showing  the  imme- 
diate results  of  in- 
jection of  skatol. 
Note  the  hyperchro- 
matism. 
Effect  ox  Braix-cells  of  Skatol  Injection.      (Camera  hicida  drawings.) 


showing  the  late  results 
of  injection  of  skatol. 
Note  the  chromatol- 
ysis. 


■HI 

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7    ^^'■r•V                                 III     u 

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■  J/' 

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3-n.;,    AfVr 

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Cannon  test  for  adrenalin,  demonstrating  the   increased  output  of  adrenalin  after 
injection  of  skatol. 

Fig.  65. — Activatiox  of  Kinetic  System  Caused  by  Injection  of  Skatol. 
These  Illustrations  Indicate  the  Explanation  of  the  General  Ex- 
haustion Shown  in  Cases  of  Auto-intoxication. 


200 


THE   EMOTIONS 


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THE    KINETIC    SYSTEM 


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202  THE    EMOTIONS 

In  our  crossed  circulation  experiments  we  found  that  ad- 
renalin alone  could  cause  increased  brain  activity,  while 
histologically  we  know  that  adrenalin  alone  causes  an  in- 
crease of  the  Nissl  substance.  An  animal,  both  of  whose 
adrenals  had  been  excised,  showed  no  hyperchromatism 
in  the  brain-cells  after  the  injection  of  strychnin,  toxins, 
foreign  proteins,  etc.  (3)  When  the  adrenal  nerve  supply 
is  divided  (Cannon-Elliott),  then  there  is  no  increased 
adrenal  activity  in  response  to  adequate  stimuli. 

From  these  studies  we  are  forced  to  conclude  not  only  that 
the  brain  and  adrenals  are  interdependent,  but  that  the 
brain  is  actually  more  dependent  upon  the  adrenals  than  the 
adrenals  upon  the  brain,  since  the  brain  deteriorates  pro- 
gressively to  death  without  the  adrenals,  while  the  adrenal 
whose  connection  with  the  brain  has  been  broken  by  the 
division  of  its  nerve  supply  will  still  produce  sufficient  ad- 
renalin to  support  life. 

From  the  strong  affinity  of  the  brain-cells  for  adrenahn 
which  was  manifested  in  our  experiments  we  may  strongly 
suspect  that  the  Nissl  substance  is  a  volatile,  extremely 
unstable  combination  of  certain  elements  of  the  brain-cells 
and  adrenalin,  because  the  adrenals  alone  do  not  take  the 
Nissl  stain  and  the  brain  deprived  of  adrenalin  also  does 
not  take  Nissl  stain.  The  consumption  of  the  Nissl  sub- 
stance in  the  brain-cells  is  lessened  or  prevented  by  mor- 
phin,  as  is  the  output  of  adrenalin;  and  the  consumption  of 
the  Nissl  substance  is  also  lessened  or  prevented  by  nitrous 
oxid.  But  morphin  does  not  prevent  the  action  of  adrenahn 
injected  into  the  circulation,  hence  the  control  of  morphin 
over  energy  expenditure  is  exerted  directly  on  the  brain- 
cells.     Apparently    morphin    and    nitrous    oxid    both    act 


THE    KINETIC    SYSTEM 


203 


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THE    KINETIC    SYSTEM  205 

through  this  interference  with  oxidation  in  the  brain.  We, 
therefore,  conclude  that  within  a  certain  range  of  acidity  of 
the  blood  adrenalin  can  unite  with  the  brain-cells  only 
through  the  mediation  of  oxygen,  and  that  the  combination 
of  adrenalin,  oxygen,  and  certain  brain-cell  constituents 
causes  the  electric  discharge  that  produces  heat  and  motion. 
In  this  interrelation  of  the  brain  and  the  adrenals  we 
have  what  is,  perhaps,  the  master  key  to  the  automatic 
action  of  the  body.  Through  the  special  senses  environ- 
mental stimuli  reach  the  brain  and  cause  it  to  liberate  energy, 
which  in  turn  activates  certain  other  organs  and  tissues, 
among  which  are  the  adrenals.  The  increased  output  of 
adrenalin  activates  the  brain  to  still  greater  activity,  as  a 
result  of  w^hich  again  the  entire  sympathetic  nervous  sys- 
tem is  further  activated,  as  is  manifested  by  increased  heart 
action,  more  rapid  respiration,  raised  blood-pressure,  in- 
creased output  of  glycogen,  increased  power  of  the  muscles 
to  metabolize  glucose,  etc. 

If  this  conclusion  be  well  founded,  we  should  find  corrob- 
orative evidence  in  histologic  changes  in  that  great  store- 
house of  potential  energy,  the  liver,  as  a  result  of  the  apphca- 
tion  of  each  of  the  adequate  stimuli  which  produced  brain- 
cell  and  adrenal  changes. 

The  Liver 
Prolonged  insomnia,  prolonged  physical  exertion,  infec- 
tions, injections  of  toxins  and  of  strychnin,  rage  and  fear, 
physical  injury  under  anesthesia,  in  fact,  all  the  adequate 
stimuh  which  affected  the  brain  and  the  adrenals,  pro- 
duced constant  and  identical  histologic  changes  in  the  liver — 
the  cells  stained  poorly,  the  cytoplasm  was  vacuolated,  the 


206  THE    EMOTIONS 

nuclei  were  crenated,  the  cell  membranes  were  irregular,  the 
most  marked  changes  occurring  in  the  cells  of  the  periphery 
of  the  lobules  (Figs.  69  and  70).  In  prolonged  insomnia  the 
striking  changes  in  the  liver  were  repaired  by  one  seance  of 
sleep. 

Are  the  histologic  changes  in  the  liver  cells  due  to  metab- 
olism or  toxic  products,  or  are  they  ''work"  changes  inci- 
dent to  the  conversion  of  latent  into  kinetic  energy?  Are 
the  brain,  adrenals,  and  liver  interdependent?  The  fol- 
lowing facts  establish  the  answers  to  these  queries : 

(1)  The  duration  of  life  after  excision  of  the  liver  is  about 
the  same  as  after  adrenalectomy — approximately  eighteen 
hours. 

(2)  The  amount  of  glycogen  in  the  liver  was  diminished 
in  all  the  experiments  showing  brain-adrenal  activity;  and 
when  the  histologic  changes  were  repaired,  the  normal 
amount  of  glycogen  was  again  found. 

(3)  In  crossed  circulation  experiments  changes  were 
found  in  the  liver  of  the  animal  whose  brain  received  the 
stimulus. 

From  these  premises  we  must  consider  that  the  brain,  the 
adrenals,  and  the  liver  are  mutually  dependent  on  one  an- 
other for  the  conversion  of  latent  into  kinetic  energy.  Each 
is  a  vital  organ,  each  equally  vital.  It  may  be  said  that 
excision  of  the  brain  may  apparently  cause  death  in  less 
time  than  excision  of  the  liver  or  adrenals,  but  this  state- 
ment must  be  modified  by  our  definition  of  death.  If  all  the 
brain  of  an  animal  be  removed  by  decapitation,  its  body  may 
live  on  for  at  least  eleven  hours  if  its  circulation  be  main- 
tained by  transfusion.  An  animal  may  live  for  weeks  or 
months  after  excision  of  the  cerebral  hemispheres  and  the 


THE    KINETIC    SYSTEM 


207 


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208 


THE    EMOTIONS 


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14 


THE    KINETIC    SYSTEM  211 

cerebellum,  while  an  overtransfused  animal  may  live  many 
hours,  days  even,  after  the  destruction  of  the  medulla.  It 
is  possible  even  that  the  brain  actually  is  a  less  vital  organ 
than  either  the  adrenals  or  the  liver. 

In  our  research  to  discover  whether  any  other  organs 
should  be  included  with  the  brain,  the  adrenals,  and  the 
liver  in  this  mutually  interdependent  relation,  we  hit  upon 
an  experiment  which  throws  light  upon  this  problem. 

Groups  of  rabbits  were  gently  kept  awake  for  one  hundred 
hours  by  relays  of  students,  an  experiment  which  steadily 
withdrew  energy  but  caused  not  the  slightest  physical  or 
emotional  injury  to  any  of  them;  no  drug,  toxin,  or  other 
agent  was  given  to  them ;  they  were  given  sufficient  food  and 
drink.  In  brief,  the  internal  and  external  environments 
of  these  animals  were  kept  otherwise  normal  excepting  for 
the  gentle  stimuli  which  insured  continued  wakefulness. 
This  protracted  insomnia  gradually  exhausted  the  animals 
completely,  some  to  the  point  of  death  even.  Some  of  the 
survivors  were  killed  immediately  after  the  expiration  of 
one  hundred  hours  of  wakefulness,  others  after  varying 
intervals. 

Histologic  studies  were  made  of  every  tissue  and  organ 
in  the  body.  Three  organs,  the  brain,  the  adrenals,  and 
the  liver,  and  these  three  only,  showed  histologic  changes. 
In  these  three  organs  the  histologic  changes  were  marked, 
and  were  almost  wholly  repaired  by  one  seance  of  sleep.  In 
each  instance  these  histologic  changes  were  identical  with 
those  seen  after  physical  exertion,  emotions,  toxins,  etc.*     It 

*  Further  studies  have  given  evidence  that  the  elimination  of  the  acids  re- 
sulting from  energy-transformation  as  well  as  the  conversion  of  energy  stored 
in  the  kinetic  organs  causes  histologic  changes  in  the  liver,  the  adrenals,  and 
possibly  in  the  brain. 


212  THE    EMOTIONS 

would  appear,  then,  that  these  three  organs  take  the  stress 
of  life — the  brain  is  the  ''battery,"  the  adrenals  the  "oxy- 
dizer,"  and  the  hver  the  "gasoline  tank."  This  clear-cut 
insomnia  experiment  corresponds  precisely  with  our  other 
brain-adrenal  observations. 

With  these  three  kinetic  organs  we  may  surely  associate 
also  the  "furnace,"  the  muscles,  in  which  the  energy  pro- 
vided by  the  brain,  adrenals,  and  liver,  plus  oxygen,  is 
fabricated  into  heat  and  motion. 

Benedict,  in  his  monumental  work  on  metabolism,  has 
demonstrated  that  in  the  normal  state,  at  least,  variations  in 
the  heart-beat  parallel  variations  in  metabolism.  He  and 
others  have  shown  also  that  all  the  energy  of  the  body, 
whether  evidenced  by  heat  or  by  motion,  is  produced  in  the 
muscles.  In  the  muscles,  then,  we  find  the  fourth  vital  link 
in  the  kinetic  chain.  The  muscles  move  the  body,  circulate 
the  blood,  effect  respiration,  and  govern  the  body  tempera- 
ture. They  are  the  passive  servants  of  the  brain-adrenal- 
liver  syndrome. 

Neither  the  brain,  the  adrenals,  the  liver,  nor  the  muscles, 
however,  nor  all  of  these  together,  have  the  power  to  change 
the  rate  of  the  expenditure  of  energy;  to  make  possible  the 
increased  expenditure  in  adolescence,  in  pregnancy,  in  court- 
ing, and  mating,  in  infections.  No  one  of  these  organs,  nor 
all  of  them  together,  can  act  as  a  pace-maker  or  sensitizer. 
The  brain  acts  immediately  in  response  to  the  stimuli  of  the 
moment;  the  adrenals  respond  instantly  to  the  fickle  brain 
and  the  effects  of  their  actions  are  fleeting;  the  liver  contains 
fuel  only  and  cannot  activate,  and  the  muscles  in  turn  act 
as  the  great  furnace  in  which  the  final  transformation  into 
available  energy  is  made. 


THE    KINETIC    SYSTEM  213 

The  Thyroid 

Another  organ — the  thyroid — has  the  special  power  of 
governing  the  rate  of  discharge  of  energy;  in  other  words, 
the  thyroid  is  the  pace-maker.  Unfortunately,  the  thyroid 
cannot  be  studied  to  advantage  either  functionally  or  histo- 
logically, for  there  is  as  yet  no  available  test  for  thyroid  se- 
cretion in  the  blood  as  there  is  for  adrenalin,  and  thyroid 
activity  is  not  attended  by  striking  histologic  changes. 
Therefore  the  only  laboratory  studies  which  have  been 
satisfactory  thus  far  are  those  by  which  the  iodin  content  of 
the  thyroid  has  been  established.  Iodin  is  stored  in  the 
colloid  lacunae  of  the  thyroid  and,  in  combination  with  cer- 
tain proteins,  is  the  active  agent  of  the  thyroid. 

Beebe  has  shown  that  electric  stimulation  of  the  nerve 
supply  of  the  thyroid  diminishes  the  amount  of  iodin  which 
it  contains,  and  it  is  known  that  in  the  hyperactive  thyroid 
in  Graves'  disease  the  iodin  content  is  diminished.  The 
meagerness  of  laboratory  studies,  however,  is  amply  com- 
pensated by  the  observations  which  the  surgeon  has  been 
able  to  make  on  a  vast  scale — observations  which  are  as 
definite  as  are  the  results  of  laboratory  experiments. 

The  brain-cells  and  the  adrenals  are  securely  concealed 
from  the  eye  of  the  clinician,  hence  the  changes  produced 
in  them  by  different  causes  escape  his  notice,  but  the  thyroid 
has  always  been  closely  scrutinized  by  him.  The  clinician 
knows  that  every  one  of  the  above-mentioned  causes  of 
increased  brain-cell,  adrenal,  liver  and  muscle  activity  may 
cause  an  increase  in  the  activity  of  both  the  normal  or  the 
enlarged  thyroid;  and  he  knows  only  too  well  that  in  a  given 
case  of  exophthalmic  goiter  the  same  stimuli  which  excite 


214  THE    EMOTIONS 

the  brain,  the  adrenals,  the  liver,  and  the  muscles  to  in- 
creased activity  will  also  aggravate  this  disease. 

The  function  of  the  thyroid  in  the  kinetic  chain  is  best 
evidenced,  however,  by  its  role  in  the  production  of  fever. 
Fever  results  from  the  administration  of  thyroid  extract 
alone  in  large  doses.  In  the  hyperactivity  of  the  thyroid  in 
exophthalmic  goiter  one  sees  a  marked  tendency  to  fever; 
in  severe  cases  there  is  daily  fever.  In  fact,  in  Graves' 
disease  we  find  displayed  to  an  extraordinary  degree  an 
exaggeration  of  the  whole  action  of  the  kinetic  mechanism. 

We  have  stated  that  in  acute  Graves'  disease  there  is  a 
tendency  to  the  production  of  spontaneous  fever,  and  that 
there  is  a  magnified  diurnal  variation  in  temperature  which 
is  due  to  an  increased  output  of  energy  in  even  the  nor- 
mal reaction  producing  consciousness.  In  Graves'  disease 
there  is,  therefore,  a  state  of  intensified  consciousness,  which 
is  associated  with  low  brain  thresholds  to  all  stimuli — both 
to  stimuli  that  cause  muscular  action  and  to  stimuli  that 
cause  fever.  The  intensity  of  the  kinetic  discharge  is  seen 
in  the  constant  fine  tremor.  It  is  evident  that  the  thresholds 
of  the  brain  have  been  sensitized.  In  this  hypersensitiza- 
tion  we  find  the  following  strong  evidence  as  to  the  identity 
of  the  various  mechanisms  for  the  production  of  fever.  In 
the  state  of  superlative  sensitization  which  is  seen  in  Graves' 
disease  we  find  that  the  stimuli  that  produce  muscular 
movement,  the  stimuli  that  produce  emotional  phenomena, 
and  the  stimuli  that  produce  fever  are  as  nearly  as  can  be 
ascertained  equally  effective.  Clinical  evidence  regarding 
this  point  is  abundant,  for  in  patients  with  Graves'  disease 
we  find  that  the  three  types  of  conversion  of  energy  resulting 
from  emotional  stimulation,  from  infection  stimulation,  and 


THE    KINETIC    SYSTEM  215 

from  nociceptor  stimulation  (pain),  are,  as  nearly  as  can  be 
judged,  equally  exaggerated.  In  the  acute  cases  of  Graves' 
disease  the  explosive  conversion  of  latent  energy  into  heat 
and  motion  is  unexcelled  bj^  any  other  known  normal  or 
pathologic  phenomenon.  Excessive  thyroid  secretion,  as 
in  thyrotoxicosis  from  functioning  adenomata,  and  exces- 
sive thyroid  feeding,  cause  all  the  phenomena  of  Graves' 
disease  except  the  exophthalmos  and  the  emotional  facies 
(Figs.  15  and  23).  The  ligation  of  arteries,  the  division  of 
its  nerve  supply,  or  the  excision  of  part  of  the  gland,  may 
reverse  the  foregoing  picture  and  restore  the  normal  con- 
dition. The  patient  notes  the  effect  on  the  second  day  and 
often  within  a  week  is  relatively  quiescent.  On  the  con- 
trary, if  there  is  thyroid  deficiency  there  results  the  opposite 
state,  a  reptilian  sluggishness. 

At  will,  then,  through  diminished,  normal,  or  excessive 
administration  of  thyroid  secretion,  we  may  produce  an 
adynamic,  a  normal,  or  an  excessively  dynamic  state.  By 
the  thyroid  influence,  the  brain  thresholds  are  lowered  and 
life  becomes  exquisite;  without  its  influence  the  brain 
becomes  a  globe  of  relatively  inert  substance.  Excessive 
doses  of  iodin  alone  cause  most  of  the  symptoms  of  Graves' 
disease.  As  we  have  stated,  the  active  constituent  of  the 
thyroid  is  iodin  in  a  special  protein  combination  which  is 
stored  in  the  colloidal  spaces.  Hence  one  would  not  expect 
to  find  changes  in  the  cells  of  the  thyroid  gland  as  a  result 
of  increased  activity  unless  it  be  prolonged. 

We  have  thus  far  considered  the  normal  roles  played  by  the 
brain,  the  adrenals  the  liver,  the  muscles,  and  the  thyroid  in 
transforming  latent  into  kinetic  energy  in  the  form  of  heat 
and  motion  as  an  adaptive  response  to  environmental  stimuli. 


216  THE    EMOTIONS 

The  argument  may  be  strengthened,  however,  by  the 
discussion  of  the  effect  of  the  impairment  of  any  of  these 
Knks  in  the  kinetic  chain  upon  the  conversion  of  latent  into 
kinetic  energy. 

Effect  Upon  the  Otitptit  of  Energy  of  Impaired  or  Lost  Function 
of  Each  of  the  Several  Links  in  the  Kinetic  Chain 

(1)  The  Brain. — In  cerebral  softening  we  may  find  all  the 
organs  of  the  body  comparatively  healthy  excepting  the 
brain.  As  the  brain  is  physically  impaired  it  cannot  nor- 
mally stimulate  other  organs  to  the  conversion  of  latent  en- 
ergy into  heat  or  into  motion,  but,  on  the  contrary,  in  these 
cases  we  find  feeble  muscular  and  intellectual  power.  I  be- 
lieve also  that  in  patients  with  cerebral  softening,  infections 
such  as  pneumonia  show  a  lower  temperature  range  than  in 
patients  whose  brains  are  normal. 

(2)  The  Adrenals. — In  such  destructive  lesions  of  the 
adrenals  as  Addison's  disease  one  of  the  cardinal  symptoms 
is  a  subnormal  temperature  and  impaired  muscular  power. 
Animals  upon  whom  double  adrenalectomy  has  been  per- 
formed show  a  striking  fall  in  temperature,  muscular  weak- 
ness,— after  adrenalectomy  the  animal  may  not  be  able  to 
stand  even, — and  progressive  chromatolysis. 

(3)  The  Liver. — When  the  function  of  the  liver  is  impaired 
by  tumors,  cirrhosis,  or  degeneration  of  the  liver  itself,  then 
the  entire  energy  of  the  body  is  correspondingly  diminished. 
This  diminution  of  energy  is  evidenced  by  muscular  and 
mental  weakness,  by  diminished  response  and  by  gradual 
loss  of  efficiency  which  finally  reaches  the  state  of  asthenia. 

(4)  The  Muscles. — It  has  been  observed  clinically  that  if 
the  muscles  are  impaired  by  long  disuse,  or  by  a  disease  such 


THE    KINETIC    SYSTEM  217 

as  myasthenia  gravis,  then  the  range  of  production  of  both 
heat  and  motion  is  below  normal.  This  is  in  agreement  with 
the  experimental  findings  that  anesthetics,  curare,  or  any 
break  in  the  muscle-brain  connection  causes  diminished 
muscular  and  heaj:  production. 

(5)  The  Thyroid. — In  myxedema  one  of  the  cardinal 
symptoms  is  a  persistently  subnormal  temperature  and, 
though  prone  to  infection,  subjects  of  myxedema  show  but 
feeble  febrile  response  and  readily  succumb.  This  clinical 
observation  is  strikingly  confirmed  by  laboratory  observa- 
tions; normal  rabbits  subjected  to  fear  showed  a  rise  in 
temperature  of  from  one  to  three  degrees,  while  two  rabbits 
whose  thyroids  had  been  previously  removed  and  who  had 
then  been  subjected  to  fright  showed  much  less  febrile 
response.  Myxedema  subjects  show  a  loss  of  physical  and 
mental  energy  which  is  proportional  to  the  lack  of  thyroid. 
Deficiency  in  any  of  the  organs  of  the  kinetic  chain  causes 
alike  loss  of  heat,  loss  of  muscular  and  emotional  action,  of 
mental  power,  and  of  the  power  of  combating  infections — 
the  negative  evidence  thus  strongly  supports  the  positive. 
By  accumulating  all  the  evidence  we  believe  we  are  justified 
in  associating  the  brain,  the  adrenals,  the  thyroid,  the 
muscles,  and  the  liver  as  vital  links  in  the  kinetic  chain. 
Other  organs  play  a  role  undoubtedly,  though  a  minor  one. 

Stwdies   in  Hydrogen  Ion    Concentration    in   Activation    of   the 

Kinetic  System 

Having  established  the  identity  of  some,  at  least,  of  the 
organs  which  constitute  the  kinetic  chain,  we  endeavored  to 
secure  still  further  evidence  regarding  the  energy-trans- 
forming function  of  these  organs  by  making  studies  of  the 


218  THE    EMOTIONS 

H-ion  concentration  of  the  blood,  as  one  would  expect, 
-prima  facie,  that  the  normal  reaction  would  be  altered  by 
kinetic  activation.* 

H-ion  concentration  tests  were  made  after  the  application 
of  the  adequate  stimuli  by  which  the  function  of  the  kinetic 
organs  had  been  determined,  and  we  studied  also  the  effect 
upon  the  acidity  of  the  blood  of  strychnin  convulsions 
after  destruction  of  the  medulla;  of  deep  narcotization  with 
morphin  before  anesthesia;  of  deep  narcotization  with 
morphin  after  the  H-ion  concentration  had  already  been 
increased  by  fear,  by  anger,  by  exertion,  by  injury  under 
anesthesia,  or  by  anesthesia  alone. 

The  complete  data  of  these  experiments  will  be  later 
reported  in  a  monograph;  here  it  is  sufficient  to  state  that 
anger,  fear,  injury,  muscular  exertion,  inhalation  anesthesia, 
strychnin,  alcohol,  in  fact,  all  the  stimuli  which  we  had 
already  found  to  produce  histologic  changes  in  the  brain, 
the  adrenals,  and  the  liver — excepting  bacterial  toxins — 
caused  increased  H-ion  concentration.  Of  striking  signi- 
ficance is  the  fact  that  morphin  alone  caused  no  change  in 
the  H-ion  concentration,  while  if  administered  before  the 
application  of  a  stimulus  which  by  itself  produced  increased 
H-ion  concentration,  the  action  of  that  stimulus  was  neu- 
tralized or  postponed.  If,  however,  morphin  was  admin- 
istered after  increased  acidity  had  been  produced  by  any 
stimulus,  or  by  inhalation  anesthesia,  then  the  time  required 
for  the  restoration  of  the  normal  alkalinity  was  much  pro- 
longed, and  in  some  instances  the  power  of  acid  neutraliza- 
tion was  permanently  lost. 

After  excision  of  the  liver,  the  normal  H-ion  concentration 

*  The  H-ion  observations  were  made  in  my  laboratory  by  Dr.  M.  L.  Menten. 


THE    KINETIC    SYSTEM  219 

was  maintained  for  periods  varying  from  one  to  several 
hours,  after  which  the  concentration  (acidity)  began  to 
increase  as  the  vitaUty  of  the  animal  began  to  decline,  the 
concentration  (acidit}')  increasing  rapidly  until  death. 
After  excision  of  the  adrenals  the  blood  remained  normal 
for  from  four  to  six  hours,  when  the  H-ion  concentration 
increased  rather  suddenly,  the  increase  being  synchronous 
with  the  incidence  of  the  phenomena  which  immediately 
preceded  death. 

In  none  of  these  cases  was  it  determined  whether  the  in- 
creased H-:on  concentration  was  due  to  other  causes  of 
death  or  whether  death  was  due  to  the  increased  acidity. 

It  is  also  significant  that  after  the  application  of  each  of 
the  adequate  stimuli  which  increased  the  H-ion  concentra- 
tion of  the  blood  in  other  parts  of  the  body  the  blood  from 
the  adrenal  vein  showed  a  slight  diminution  in  acidity,  as, 
in  most  instances,  did  the  blood  from  the  hepatic  vein  also. 

In  fact,  the  H-ion  concentration  of  the  blood  in  the  adrenal 
vein  was  less  than  in  the  blood  of  any  other  part  of  the  cir- 
culation. 

Kinetic  Diseases 

If  our  conclusions  are  sound,  then  in  the  kinetic  system 
we  find  an  explanation  of  many  diseases,  and  having  found 
the  explanation,  we  may  find  new  methods  of  combating 
them. 

"Wlien  the  kinetic  system  is  driven  at  an  overwhelming 
rate  of  speed, — as  by  severe  physical  injury,  by  intense 
emotional  excitation,  by  perforation  of  the  intestines,  by 
the  pointing  of  an  abscess  into  new  territory,  by  the  sudden 
onset  of  an  infectious  disease,  by  an  overdose  of  strychnin, 


220  THE   EMOTIONS 

by  a  Marathon  race,  by  a  grilling  fight,  by  foreign  proteins, 
by  anaphylaxis, — the  result  of  these  acute  overwhelming 
activations  of  the  kinetic  system  is  clinically  designated 
shock,  and  according  to  the  cause  is  called  traumatic  shock, 
toxic  shock,  anaphylactic  shock,  drug  shock,  etc. 

The  essential  pathology  of  shock  is  identical  whatever  the 
cause.  If,  however,  instead  of  an  intense  overwhelming 
activation,  the  kinetic  system  is  continuously  or  intermit- 
tently overstimulated  through  a  considerable  period  of  time, 
as  long  as  each  of  the  hnks  in  the  kinetic  chain  takes  the 
strain  equally  the  result  will  be  excessive  energy  conversion, 
excessive  work  done ;  but  usually,  under  stress,  some  one 
link  in  the  chain  is  unable  to  take  the  strain  and  then  the 
evenly  balanced  work  of  the  several  organs  of  the  kinetic 
system  is  disturbed.  If  the  brain  cannot  endure  the  strain, 
then  neurasthenia,  nerve  exhaustion,  or  even  insanity  fol- 
lows. If  the  thyroid  cannot  endure  the  strain,  it  under- 
goes hyperplasia,  which  in  turn  may  result  in  a  colloid  goiter 
or  in  exophthalmic  goiter.  If  the  adrenals  cannot  endure 
the  strain,  cardiovascular  disease  may  develop.  If  the  Uver 
cannot  take  the  strain,  then  death  from  acute  acidosis  may 
follow,  or  if  the  neutralizing  effect  of  the  liver  is  only  partially 
lost,  then  the  acidity  may  cause  Bright' s  disease.  Over- 
activation  of  the  kinetic  system  may  cause  glycosuria  and 
diabetes. 

Identical  physical  and  functional  changes  in  the  organs  of 
the  kinetic  sj^stem  may  result  from  intense  continued  stimu- 
lation from  any  of  the  following  causes:  Excessive  physical 
labor,  athletic  exercise,  worry  or  anxiety,  intestinal  auto- 
intoxication, chronic  infections,  such  as  oral  sepsis,  tonsillitis, 
and  adenoids;    chronic  appendicitis,   chronic  cholecystitis, 


THE    KINETIC    SYSTEM  221 

colitis,  and  skin  infections;  the  excessive  intake  of  protein 
food  (foreign  protein  reaction) ;  emotional  strain,  pregnancy, 
stress  of  business  or  professional  life — all  of  which  are  known 
to  be  activators  of  the  kinetic  system. 

From  the  foregoing  statements  we  are  able  to  understand 
the  muscular  weakness  following  fever;  we  can  understand 
why  the  senile  have  neither  muscular  power  nor  strong 
febrile  reaction;  why  long-continued  infections  produce 
pathologic  changes  in  the  organs  constituting  the  kinetic 
chain ;  why  the  same  pathologic  changes  result  from  various 
forms  of  activation  of  the  kinetic  system.  In  this  hypothesis 
we  find  a  reason  why  cardiovascular  disease  may  be  caused 
by  chronic  infection,  by  auto-intoxication,  by  overwork, 
or  by  emotional  excitation.  We  now  see  that  the  reason 
why  we  find  so  much  difficulty  in  differentiating  the  numer- 
ous acute  infections  from  each  other  is  because  they  play 
upon  the  same  kinetic  chain.  Our  postulate  harmonizes 
the  pathologic  democracy  of  the  kinetic  organs,  for  it  ex- 
plains not  only  why,  in  many  diseases,  the  pathologic 
changes  in  these  organs  are  identical,  but  why  the  same 
changes  are  seen  as  the  result  of  emotional  strain  and  over- 
work. We  can  thus  understand  how  either  emotional  strain 
or  acute  or  chronic  infection  may  cause  either  exophthalmic 
goiter  or  cardiovascular  disease;  how  chronic  intestinal 
stasis  with  the  resultant  absorption  of  toxins  may  cause 
cardiovascular  disease,  neurasthenia,  or  goiter.  Here  is 
found  an  explanation  of  the  phenomena  of  shock,  whether 
the  shock  be  the  result  of  toxins,  of  infection,  of  foreign 
proteins,  of  anaphylaxis,  of  psychic  stimuli,  or  of  a  surgical 
operation  with  its  combination  of  both  psychic  and  trau- 
matic elements. 


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224  THE    EMOTIONS 

This  conception  of  the  kinetic  system  has  stood  a  crucial 
test  by  making  possible  the  shockless  operation.  It  has 
offered  a  plausible  explanation  of  the  cause  and  the  treat- 
ment of  Graves'  disease.  Will  the  kinetic  theory  stand  also 
the  clinical  test  of  controlling  that  protean  disease  bred  in  the 
midst  of  the  stress  of  our  present-day  life?  Present-day 
life,  in  which  one  must  ever  have  one  hand  on  the  sword  and 
the  other  on  the  throttle,  is  a  constant  stimulus  of  the  kinetic 
system.  The  force  of  these  kinetic  stimuli  may  be  lessened 
at  the  cerebral  Unk  by  intelligent  control — a  protective 
control  is  empirically  attained  by  many  of  the  most  success- 
ful men.  The  force  of  the  kinetic  stimuli  may  be  broken  at 
the  thyroid  link  by  dividing  the  nerve  supply,  reducing  the 
blood  supply,  or  by  partial  excision;  or  if  the  adrenals 
feel  the  strain,  the  stimulating  force  may  be  broken  by  divid- 
ing their  nerve  supply,  reducing  the  blood  supply,  or  by 
partial  excision.  No  theory  is  worth  more  than  its  yield  in 
practice,  but  already  we  have  the  shockless  operation,  the 
surgical  treatment  of  Graves'  disease,  and  the  control  of 
shock  and  of  the  acute  infections  by  overwhelming  mor- 
phinization  (Figs.  62,  72,  and  73).    . 


Concltisions 
To  become  adapted  to  their  environment  animals  are 
transformers  of  energy.  This  adaptation  to  environment  is 
made  by  means  of  a  system  of  organs  evolved  for  the  purpose 
of  converting  potential  energy  into  heat  and  motion.  The 
principal  organs  and  tissues  of  this  system  are  the  brain,  the 
adrenals,  the  thyroid,  the  muscles,  and  the  liver.  Each  is 
a  vital  link,  each  plays  its  particular  role,  and  one  cannot 


THE    KINETIC    SYSTEM  225 

compensate  for  the  other.  A  change  in  any  Unk  of  the 
kinetic  chain  modifies  proportionately  the  entire  kinetic 
system  which  is  no  stronger  than  its  weakest  link. 

In  this  conception  we  find  a  possible  explanation  of  many 
diseases  one  which  may  point  the  way  to  new  and  more 
effective  therapeutic  measures  than  those  now  at  our  com- 
mand. 


15 


ALKALESCENCE,  ACIDITY,  ANESTHESIA— A  THEORY  OF 

ANESTHESIA* 

Alkalis  and  bases  compose  the  greater  part  of  the  food  of 
man  and  animals,  the  blood  in  both  man  and  animals  under 
normal  conditions  being  slightly  alkaline  or  rather  potentially 
alkaline;  that  is,  although  in  circulating  blood  the  concen- 
tration of  the  OH-ions — upon  which  the  degree  of  alkalinity 
depends —  is  but  little  more  than  in  distilled  water,  yet  blood 
has  the  power  of  neutralizing  a  considerable  amount  of  acid 
(Starling,  Wells).  At  the  time  of  death,  whatever  its  cause, 
the  concentration  of  H-ions  in  the  blood  increases, — the 
concentration  of  H-ions  being  a  measure  of  acidity, — that 
is,  the  potential  or  actual  alkalinity  decreases  and  the  blood 
becomes  actually  neutral  or  acid. 

To  determine  what  conditions  tend  to  diminish  the  normal 
alkalinity  of  the  blood,  many  observations  were  made  for 
me  in  my  laboratory  by  Dr.  M.  L.  Menten  to  determine  by 
electric  measurements  the  H-ion  concentration  of  the  blood 
under  certain  pathologic  and  physiologic  conditions. 

As  a  result  of  these  researches  we  are  able  to  state  that  the 
H-ion  concentration  of  the  blood — its  acidity — is  increased 
by  excessive  muscular  activity;  excessive  emotional  excita- 
tion; surgical  shock;  in  the  late  stages  of  infection;  by 
asphyxia;    by    strychnin   convulsions;   by  inhalation  anes- 

*  Paper  delivered  before  the  Virginia  Medical  Association,  Washington, 
D.  C,  October  29,  1914. 

227 


228  THE    EMOTIONS 

thetics;  after  excision  of  the  pancreas,  and  in  the  late  stages 
of  hfe  after  excision  of  the  hver  and  excision  of  the  adrenals. 
Morphin  and  decapitation  cause  no  change  in  the  H-ion 
concentration.  Ether,  nitrous  oxid,  and  alcohol  produce  an 
increased  acidity  of  the  blood  which  is  proportional  to  the 
depth  of  anesthesia. 

Many  of  the  cases  studied  were  near  death,  as  would  be 
expected,  since  it  is  well  known  that  a  certain  degree  of 
acidity  is  incompatible  with  life. 

Since  alkalis  and  bases  preponderate  in  ingested  food; 
since  alkalinity  of  the  blood  is  diminished  by  bodily  activity; 
and  since  at  the  point  of  death  the  blood  is  always  acid,  we 
may  infer  that  some  mechanism  or  mechanisms  of  the  body 
were  evolved  for  the  purpose  of  changing  bases  into  acids 
that  thus  energy  might  be  liberated. 

These  observations  lead  naturally  to  the  question.  May 
not  acidity  of  itself  be  the  actual  final  cause  of  death?  We 
believe  that  it  may  be  so  from  the  facts  that — (1)  The  in- 
travenous injection  of  certain  acids  causes  death  quickly,  but 
that  convulsions  do  not  occur,  since  the  voluntary  muscles 
lose  their  power  of  contraction;  and  (2)  the  intravenous 
injection  of  acids  causes  extensive  histologic  changes  in  the 
brain,  the  adrenals,  and  the  liver  which  resemble  the  changes 
invariably  caused  by  activation  of  the  kinetic  system  (Figs. 
74  and  75),  In  view  of  these  facts  may  we  not  find  that 
anesthesia  and  many  instances  of  unconsciousness  are  merely 
phenomena  of  acidity? 

As  has  been  stated  already,  we  have  found  that  the  H-ion 
concentration  of  the  blood — its  acidity — is  increased  by 
alcohol,  by  ether,  and  by  nitrous  oxid.  In  addition  our 
tests  have  shown  that  under  ether  the  increase  of  the  H-ion 


ALKALESCENCE,    ACIDITY,    ANESTHESL\ 


229 


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THE    EMOTIONS 


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ALKALESCENCE,   ACIDITY,    ANESTHESIA  231 

concentration — acidity — is  more  gradual  than  under  nitrous 
oxid,  an  observation  which  accords  well  with  the  fact  that 
nitrous  oxid  more  quickl}^  induces  anesthesia  than  does  ether. 

Further  striking  testimony  in  favor  of  the  hypothesis  that 
the  production  of  acidity  by  inhalation  anesthetics  is  the 
method  by  which  anesthesia  itself  is  produced  is  found  in 
the  fact  that  although  lethal  doses  of  acid  cause  muscular 
paralysis,  yet  this  paralysis  may  be  mitigated  by  adrenalin — ■ 
which  is  alkaline.  This  observation  may  explain  in  part  the 
remarkable  success  of  the  method  of  resuscitation  devised 
by  me,  in  which  animals  ''killed"  by  anesthetics  and  as- 
phyxia are  revived  by  the  use  of  adrenalin. 

In  animals  under  inhalation  anesthesia  Williams  found 
that  no  nerve-current  could  be  detected  by  the  Einthoven 
string  galvanometer,  a  fact  which  might  be  explained  by 
postulating  that  nerve-currents  can  flow  from  the  brain  to 
the  muscles  and  glands  only  when  there  is  a  difference  of 
potential.  Any  variation  from  the  normal  alkalinity  of 
the  body  must  change  the  difference  in  potential.  Since 
the  nerve-currents  in  animals  under  anesthesia  are  not 
demonstrable  by  any  apparatus  at  our  command,  and  since 
anesthesia  produces  acidity,  then  we  may  infer  that  acidity 
reduces  the  difference  in  potential.  As  long  as  there  is  life, 
a  galvanometer  of  sufficient  delicacy  would  perforce  detect  a 
nerve-current  until  the  acidity  increased  to  such  a  point  as 
to  reduce  the  difference  in  potential  to  zero — the  point  of 
death.  If  at  this  point  a  suitable  alkali — adrenalin  solution 
— can  be  introduced  quickly  enough,  the  vital  difference  in 
potential  may  be  restored  and  the  life  processes  will  be 
renewed.  Bearing  especially  on  this  point  is  the  fact  that 
if  adrenalin  in  sufficient  quantities  be  administered  simul- 


232  THE    EMOTIONS 

taneously  with  an  acid,  it  will  not  only  prevent  the  fall  in 
blood-pressure  usually  caused  by  the  acid,  but  will  also  pre- 
vent the  histologic  changes  in  the  brain,  adrenals,  and  liver 
which  are  usually  caused  by  the  intravenous  injection  of 
acids. 

This  hypothesis  regarding  the  cause  of  anesthesia  and 
unconsciousness  explains  and  harmonizes  many  facts.  It 
explains  how  asphyxia,  overwhelming  emotion,  and  excessive 
muscular  exertion,  by  causing  acidity,  may  produce  uncon- 
sciousness. It  explains  the  acidosis  which  results  from 
starvation,  from  uremia,  from  diabetes,  from  Bright's  disease, 
and  supplies  a  reason  for  the  use  of  intravenous  infusions  of 
sodium  bicarbonate  to  overcome  the  coma  of  diabetes  and 
uremia  (Fig.  76).  It  may  explain  the  quick  death  from 
chloroform  and  nitrous  oxid;  and  may  perhaps  show  why 
unconsciousness  is  so  commonly  the  immediate  precursor  of 
death. 

One  of  the  most  noticeable  immediate  effects  of  the  ad- 
ministration of  an  inhalation  anesthetic  is  a  marked  increase 
in  the  rapidity  and  force  of  the  respiration.  The  respiratory 
center  has  evidently  been  evolved  to  act  with  an  increase  of 
vigor  which  is  proportional — within  certain  limits — to  the 
increase  in  the  H-ion  concentration,  whereas  the  centers 
governing  the  voluntary  muscles  are  inhibited.  In  this 
antithetic  reaction  of  the  higher  cortical  centers  and  the 
lower  centers  in  the  medulla  to  acidity  we  find  a  remarkable 
adaptation  which  prevents  the  animal  from  killing  itself  by 
the  further  increase  in  acidity  which  would  be  produced  by 
muscular  activity.  That  is,  as  the  acidity  produced  by 
muscular  action  increases  and  threatens  life,  the  respiratory 
action,  by  which  carbon  dioxid  is  eliminated  and  oxygen 


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234  THE    EMOTIONS 

supplied,  is  increased,  while  the  dli^^.ng  power  of  the  brain, 
which  produces  acidity,  is  diminished  or  even  inhibited 
entirely:  that  is,  the  state  of  unconsciousness  or  anesthesia 
is  reached.  We  conclude  first  that,  without  this  hfe-saving 
regulation,  animals  under  stress  would  inevitably  commit 
suicide;  and,  second,  that  it  is  probable  that  the  remarkable 
phenomenon  of  anesthesia^ — the  coincident  existence  of  un- 
consciousness and  life — is  due  to  this  antithetic  action  of 
the  cortex  and  the  medulla. 

In  the  human,  as  in  the  animal,  the  degree  of  acidit}^ 
parallels  the  depth  of  inhalation  anesthesia. 

"VTithin  a  few  seconds  after  beginning  nitrous  oxid  anes- 
thesia the  acidity  of  the  blood  is  increased.  This  rapid 
acidulation  is  sjTichronous  with  almost  instantaneous  un- 
consciousness and  increased  respiration.  If  the  oxygen  in 
the  inhaled  mixture  be  increased,  a  decrease  in  acidity  is 
again  sjTichronous  ^ith  hghter  anesthesia  and  a  decrease  in 
the  respirators^  rate. 

If  these  premises  be  sound,  we  are  justified  in  asserting 
that  the  state  of  anesthesia  is  due  to  an  induced  acidity  of 
the  blood.  If  the  acidity  is  slight,  then  the  anesthesia  is 
shght  and  the  force  of  the  nerve  impulses  is  lessened,  but  the 
patient  is  .stih  conscious  of  them.  As  the  acidity  increases 
associative  memory  is  lost,  and  the  patient  is  said  to  be 
unconscious:  the  centers  governing  the  voluntarj^  muscles 
are  not  inhibited,  however,  and  cutting  the  skin  causes 
movements.  If  the  acidity  is  further  increased,  there  is 
loss  of  muscular  tone  and  even  the  strong  contact  ceptor 
stimuh  of  a  siKgical  operation  do  not  cause  any  muscular 
response,  and,  finalh',  the  acidity  may  be  increased  to  the 
point  at  which  the  respirator}'  and  circulator}?-  centers  can 


ALKALESCENCE,    ACIDITY,   ANESTHESIA  235 

no  longer  respond  by  increased  effort,  and  anesthetic  death — 
that  is,  acid  death — follows. 

Certain  clinical  phenomena  are  clarified  by  this  theory 
and  serve  to  substantiate  it.  For  example,  it  is  well  known 
that  inhalation  anesthesia  precipitates  the  impending  acid- 
osis which  results  from  starvation,  from  extreme  Graves' 
disease,  from  great  exhaustion,  from  surgical  shock,  and  from 
hemorrhage,  and  which  is  present  when  death  from  any  cause 
is  imminent. 

We  see,  therefore,  that  anesthesia  is  made  possible,  first, 
by  the  fact  that  inhalation  anesthetics  cause  acidity,  and, 
second,  by  the  antithetic  adaptation  of  the  higher  centers  in 
the  brain  and  of  the  centers  governing  respiration  and  cir- 
culation. 

In  deep  contrast  to  the  action  of  inhalation  anesthetics  is 
that  of  narcotics.  Deep  narcotization  with  morphin  and 
scopolamin  is  induced  slowly;  the  respiratory  and  pulse-rate 
are  progressively  lessened — and  there  is  no  acidity. 

By  our  researches  we  have  established  in  what  consists 
the  generic  difference  between  inhalation  anesthetics  and 
narcotics.  In  our  experiments  no  increase  in  the  H-ion 
concentration  was  produced  by  morphin  or  by  scopolamin, 
no  matter  how  deep  the  narcotization.  In  animals  already 
narcotized  by  morphin  the  production  of  acid  by  any  of  the 
acid-producing  stimuli  was  delayed  or  prevented.  On  the 
other  hand,  in  animals  in  which  an  acidity  had  already  been 
produced  by  ether,  by  shock,  by  anger,  or  by  fear,  the  later 
administration  of  morphin  delayed  or  inhibited  entirely  the 
neutralization  of  the  acidity.  In  other  words,  morphin 
interferes  with  the  normal  mechanism  by  which  acidity  is 
neutralized  possibly  because  its  inhibiting  action  on  the 


236  THE   EMOTIONS 

respiratory  center  is  sufficient  to  overcome  the  stimulating 
action  of  acidity  on  that  center,  for,  as  we  have  stated,  the 
neutrahzation  of  acidity  is  in  large  measure  accomplished 
by  the  increased  respiration  induced  by  the  acidity  itself. 

Summary 

Acidity  inhibits  the  functions  of  the  cerebral  cortex,  but 
stimulates  those  of  the  medulla.  This  antithetic  reaction 
to  the  stimulus  of  increased  H-ion  concentration  is  an  adap- 
tation to  prevent  animals  from  committing  suicide  by  over- 
activity, for  the  mechanism  for  the  initiation  and  control 
of  the  transformation  of  energy  is  in  the  higher  centers  of  the 
brain,  while  an  essential  part  of  the  mechanism  for  the 
neutralization  of  acidity — the  centers  governing  circulation 
and  respiration — is  in  the  medulla.  This  explains  many 
clinical  phenomena — why  excessive  acidity  causes  paralysis ; 
why  there  is  great  thirst  after  inhalation  anesthesia,  after 
excessive  muscular  activity,  excessive  emotion — after  all 
those  activities  which  we  have  found  to  be  acid-producing, 
for  water,  like  air,  neutralizes  acids.  The  excessive  use  of 
alcohol,  anesthetics,  excessive  work,  intense  emotion,  all 
produce  lesions  of  the  kidney  and  of  the  liver.  The  ex- 
planation is  found  in  the  fact  that  all  these  stimuli  increase 
the  acidity  of  the  blood,  and  that,  if  long  continued,  the 
neutralizing  mechanism  must  be  broken  down  and  so  the 
end-products  of  metabolism  are  insufficiently  prepared  for 
elimination. 

In  view  of  these  considerations  we  may  well  conclude  that 
the  maintenance  of  the  normal  potential  alkalinity  of  the 
blood  is  to  be  estimated  as  the  keystone  of  the  foundation 
of  life  itself. 


NDEX 


Abdomen,   diseases  of,   phylogenetic 

association  and,  44 
Acidity,  227 
Adaptive  energy,  176 

variation   in   rate    of    energy    dis- 
charge, 177 
Adrenalin,  Cannon's  test  for,  134,  196 
injection  of,  changes  in  brain-cells 
from,  186 
Adrenals,  196 

brain  and,  relation  of,  198 
diseases  of,  effect  of,  on  output  of 

energy,  216 
functional  study  of,  196 
histologic  study  of,  198 
Alcohol,  changes  in  brain-cells  from, 

116 
Alkalescence,  227 
Anemia,  pain  of,  77 
Anesthesia,  2,  227 

anoci-association   and,    differentia- 
tion, 34 
effect  of  trauma  under,  upon  brain 

that  remains  awake,  3 
inhalation,  cause  of  exhaustion  of 
brain-cells   as  result  of   trauma 
under,  8 
theory  of,  227 
Anger,  63,  70 
Anoci-association,  34 

anesthesia  and,  differentiation,  34 
Graves'  disease  and,  36 
prevention  of  shock  by  application 
of  principle  of,  36 
Aristotle,  127 
Asher,  37 

Associational  centers,  dulled,  47 
Austin,  2,  55,  173 


Bass,  159 
Beebe,  213 
Benedict,  212 

Biologic    consideration    of    adaptive 
variation    in    amounts    of    energj^ 
stored  in  various  animals,  176 
Brain,  adrenals  and,  relation  of,  198 
diseases  of,  effect  of,  on  output  of 

energy,  216 
effect  of  trauma  under  anesthesia 

on,  3 
functions,  physical  state  of  brain- 
cells  and,  relation  between,  HI 
influence  of  fear  on,  64 
Brain-cells,   cause  of  exhaustion  of, 

as   result   of   trauma   under   in- 
halation anesthesia,  8 
changes  in,  from  alcohol,  116 

from  drugs,  113 

from  fatigue,  112 

from  fear,  112 

from  hemorrhage,  113 

from  injection  of  adrenalin,  186 

from  iodoform,  116 

from  strychnin,  113 

in  Graves'  disease,  116 

in  infections,  116 

in  insanity,  120 

in  insomnia,  1 19 
histologic   changes  in,   in  relation 

to  maintenance  of  consciousness 

and  to  production  of  emotions, 

muscular  activity,  and  fever,  182 
physical  state,  brain  functions  and, 

relation  between.  111 

Cannon,  57,  64,  68,  73,  133,  138,  196, 
202 


237 


238 


INDEX 


Cannon's  test  for  adrenalin,  134,  196 
Cells,  brain-,  cause  of  exhaustion  of, 
as    result    of    trauma    under 
inhalation  anesthesia,  8 
changes  in,  from  alcohol,  116 
from  drugs,  113 
from  fatigue,  112 
from  fear,  112 
from  hemorrhage,  113 
from    injection    of    adrenalin, 

186 
from  iodoform,  116 
from  strychnin,  113 
in  Graves'  disease,  116 
in  infections,  116 
in  insanity,  120 
in  insomnia,  119 
histologic  changes  in,  in  relation 
to  maintenance  of  conscious- 
ness   and    to    production    of 
emotions,  muscular    activity, 
and  fever,  182 
physical   state,    brain   functions 
and,  relation  between.  111 
Chemical   noci-association    in    infec- 
tions, 48 
Cold  pain,  83 

sweat,  27 
Contact  pain,  special,  78 
Crying,  90 

in  exophthalmic  goiter,  106 

Darwin,  12,  26,  30,  91,  127,  153 

on  phenomena  of  fear,  26 
Disease,  mechanistic  theory  of,  157 
Distance     receptors,     discharge     of 

energy  through  stimulation  of,  25 
Dog,  spinal,  4 
Dolley,  2,  10 
Drugs,   changes  in  brain-cells  from, 

113 


Eliot,  1 

Elliott,  202 

Energy,  adaptive,  176 


Energy,  discharge,   rate   of,  adaptive 
variation  in,  177 
nervous,  cause  of  discharge  of,  12 
as  result  of  trauma  under 
inhalation  anesthesia,  12 
discharge  of,  role  of  summation 
in,  30 
through  representation  of  in- 
jury, 25 
through    stimulation    of    dis- 
tance receptors,  25 
psychic  discharge,  25 
output    of,    effect    of    diseases    of 
adrenals  on,  216 
of  brain  on,  216 
of  liver  on,  216 
of  muscles  on,  216 
of  thyroid  on,  217 
rate  of  output,  influences  that  cause 
variation  in,  177 
Environment,  128,  130 
Evacuation  pain,  77 
Exophthalmic  goiter,  66 
crying  in,  106 
fear  and,  resemblance  between, 

68 
laughing  in,  106 


Fatigue,  changes  in  brain-cells  from, 
112 

Fear,  26,  52,  55 

changes  in  brain-cells  from,  112 
Darwin  on  phenomena  of,  26 
Graves'  disease   and,  resemblance 

between,  68 
influence  of,  on  brain,  64 
phenomena  of,  56 

Fly-trap,  Venus',  151 

Frankel,  68 

Frazier,  82 

Fimctional  study  of  adrenals,  196 


Goiter,  exophthalmic,  66 
crying  in,  106 


INDEX 


239 


Goiter,    exophthalmic,    fear   and,    re- 
semblance between,  68 

laughter  in,  106 
Graves'  disease,  66 

anoci-association  and,  36 

changes  in  brain-cells  in,  116 

crying  in,  106 

fear  and,  resemblance  between, 
68 

laughter  in,  106 


Harvey,  157 

Headache,  80 

Heat  pain,  77 

production   in  infections,   purpose 
and  mechanism,  180 

Hemorrhage,    changes   in   brain-ce'.ls 
from,  113 

Hippocrates,  127 

Histologic  changes  in  liver,  205 
stud}-  of  adrenals,  198 

Hitchings,  173 

Hodge,  10 

Homaday,  26 

Hydrogen  ion  concentration  in  acti- 
vation of  kinetic  system,  217 

Hyperthj-roidism,  42 


Infections,  changes  in  brain-cells  in, 
116 
chemical  noci-association  in,  48 
heat   production  in,   purpose   and 

mechanism,  180 
pain  of,  79 
Inhalation  anesthesia,    cause  of   ex- 
haustion of  brain-cells  as  re- 
sult of  trauma  under,  8 
trauma  under,  cause  of  discharge 
of  nervous  energy  as  result  of, 
12 
Insanity,  changes  in  brain-cells  in,  120 
Insomnia,  changes  in  brain-cells  in, 
119 
effect  of,  205 


Iodoform,  changes  in  l:)rain-cells  from, 
116 


Kinetic  diseases,  219 
reaction,  93 
system,  173 


Labor  pains,  78 
Laughter,  90 

causes  of,  91 

in  exophthalmic  goiter,  106 
Law,  Sherrington's,  24 
Light  pain,  77 

Liver,  diseases  of,  effect  of,  on  output 
of  energy,  216 

histologic  changes  in,  205 
Livingstone,  148 
Lower,  42 


Malaria,  159 

McKenzie,  162 

Mechanistic  theory  of  disease,  157 
view  of  psychology,  127 

Medical  problems,   phylogenetic  as- 
sociation in  relation  to,  1 

Menten,  2,  55,  173,  218,  227 

Muscles,  diseases  of,  effect  of,  on  out- 
put of  energy,  216 


Nagging,  46 
Nausea  pains,  78 

Nervous  energy,  cause  of  discharge 
of,  12 
as  result  of  trauma  under 
inhalation  anesthesia,  12 
discharge  of,  role  of  summation 
in,  30 
through  representation  of  in- 
jury, 25 
through    stimulation    of    dis- 
tance receptors,  25 
psychic  discharge,  25 


240 


INDEX 


Neurasthenia,  sexual,  43 

Neiu-oses,  postoperative,  46 
traumatic,  46 

Noci-association,  chemical,  in  infec- 
tions, 48 

Nociceptors,  14 

diseases  and  injuries  of  regions  not 
endowed  with,  47 

Pain,  77,  107,  144,  158 

cold,  83 

contact,  special,  78 

evacuation,  77 

heat,  77 

labor,  78 

light,  77 

nausea,  78 

of  anemia,  77 

of  infection,  79 

pleasure,  78 

post-operative,  89 

site  of,  83 

traumatic,  89 
Personality,  47 

Phylogenetic  association,  diseases  of 
abdomen  and,  44 
in    relation    to    certain   medical 
problems,  1 
to  emotions,  55 
Pleasure  pains,  78 
Postoperative  neuroses,  46 

pain,  89 
Propagation  of  species,  152 
Psychic  discharge  of  energy,  25 
Psychology,  mechanistic  view,  127 

Reaction,  kinetic,  93 
Receptors,     distance,     discharge     of 
energy  through  stimulation  of,  25 

sexual,  53 

ticklish,  19 

Self-preservation,  152 
Sexual  neurasthenia,  43 


Sexual  receptors,  53 

Sherrington,  12,  13,  14,  24,  25,  48,  52, 

132,  136,  158 
Sherrington's  law,  24 
Shock,  prevention  of,  by  application 

of  principle  of  anoci-association,  36 
Sloan,  2,  14,  55,  173 
Spinal  dog,  4 
Starling,  195,  227 
Strychnin,     changes     in     brain-cells 

from,  113 
Summation,  role  of,  in  discharge  of 

nervous  energy,  30 
Sweat,  cold,  27 


Test,  Cannon's,  for  adrenalin,   134, 

196 
Thyroid  gland,  213 

diseases  of,  effect  of,  on  output 
of  energy,  217 
Ticklish  receptors,  19 
Trauma,  cause  of  exhaustion  of  brain- 
cells  as  result  of,  under  inhala- 
tion anesthesia,  8 
effect  of,   under  anesthesia,    upon 

brain  that  remains  awake,  3 
under  inhalation  anesthesia,  cause 
of  discharge  of  nervous  energy 
as  result  of,  12 
Traumatic  neuroses,  46 
pain,  89 


Vaughan,  180 

Venus'  fly-trap,  149,  151 


Weeping,  90 
Welch,  1 
Wells,  227 
Williams,  231 
Worry,  74 


